Darrell needs a ride to the airport. he is deciding between two options:

option a is a shuttle that charges a flat rate of $42.

option b is a cab that charges an initial fee of $4.50 plus an additional $1.25 for every mile traveled.

for what number of miles will option b cost less than option a? let m represent the number of miles.

m < 12

m < 30

m < 38

m < 9