Why shouldn t the driving age be raised to 21

The conjunction so does not appropriately connect the two clauses in sentence 7. Which word should replace the word so.

Question 1 options:
for
nor
but
or
PASSAGE
Raising the Driving Age
Should the driving age be raised to 18?
Alarmed by car accidents involving teenagers, a number of states are considering raising the age for getting a license.
YES
(1) On December 29, 2005, four teenage boys from Chicago went out for a late-night drive and had a terrible accident. (2) The car spun out of control and struck several objects, including a giant light pole. (3) Two of the boys—a 16-year-old and a 17-year-old—were killed. (4) The driver of the car was just 16.
(5) The answer is raising the driving age. (6) That's why I introduced legislation to raise the driving age in Illinois from 16 to 18. (7) I realize this idea is controversial, so I could not stand by and watch one more young person die because he or she was not quite ready to be behind the wheel.
(8) All 50 states prohibit 16-year-olds from drinking alcohol, buying cigarettes, and purchasing handguns. (9) Yet somehow most states are willing to put them in charge of a car, which could potentially be a deadly weapon.
(10) Between 1995 and 2004, there were 30,917 fatalities in accidents that involved 15-to-17-year-old drivers, according to a study by the AAA Foundation for Traffic Safety. (11) About a third of those deaths were the teen drivers themselves. (12) The rest were pedestrians, passengers, and people in cars that teenage drivers struck.
(13) As an Illinois lawmaker, I cannot sit back and watch more innocent lives be claimed because of lack of experience. (14) Raising the driving age may seem burdensome to parents and busy teens, but we have to remember that this is a proposal about safety, not convenience.
—Representative John D'Amico
Democrat, Illinois State Legislature
NO
(15) If your neighbor robs a bank, should you go to jail? (16) No. (17) If your classmate gets in an accident, should your driver's license be taken away? (18) Of course not. (19) Neither situation is fair. (20) Raising the driving age will punish all young drivers for the mistakes of a few of there peers. (21) In this country we live by the principle of innocent until proven guilty. (22) Those who want to raise the driving age have labeled teens guilty before they've gotten in an accident or before they've even stepped into a car. (23) They believe that just because of your birth date, you are dangerous and must be punished by having your ability to drive taken from you.
(24) Those who favor raising the driving age say that statistics show teenagers are more likely to get into accidents than adults. (25) What they don't say is that statistics also show that men of all ages are 77 percent more likely to kill someone while driving than women. (26) If people want to save lives by raising the driving age then how about saving lives by allowing only women to drive? (27) Of course, both my mom and grandma are crazy drivers, and they shouldn’t even be allowed out on the road.
(28) Except raising the driving age won't save lives. (29) Studies show that it is inexperience, not age, that causes accidents. (30) Raising the driving age will just create inexperienced, accident-prone drivers at 18 instead of 16.
(31) Teens need the ability to drive just as much as anyone else—to get to school, to get to work, to get to sports or band practice, or just to go out with their friends. (32) Cars are necessary for mobility in this country. (33) Taking that away is a large disruption to the lives of teen-agers—for no good reason.
—Alex Koroknay-Palicz
National Youth Rights Association