Raise the driving age to 18!

after reading mr. j. brown's letter, dated august 15, i feel compelled to write and let your readers know how i feel about raising the driving age from 16 to 18. teenagers should not be allowed to drive until they are 18. only high school graduates should be given a driver's license, and only after successfully completing a driver's education class during their senior year of high school.

right now, 15-year-olds can get a practice permit and try for their license at 16. this is too young. eighteen is a better age. at 18, people are more mature and better able to make mature decisions. not all 18-year-olds are mature, but the majority of them are. at least we are more mature than 15-year-olds.
which sentence provides the best supporting point to defend the author's position?
a) teenagers should not be allowed to drive until they are 18.
b) only high school graduates should be given a driver's license.
c) some younger teenagers are perfectly mature and responsible, of course.
d) at 18, people are more mature and better able to make mature decisions.