Which of the following option is a better purchase for microwave option 1. a cash sale $120
option 2 $5 down with equal payments of $10 for 15 week
option 3 $10 down with equal payments of 5 for 24 months
option 4 zero down with equal payments of 15 for 9 months

First we have to find (f o g)(x):
(f o g)(x) = [2(7x + 1) + 2] = (14x + 2 + 2) = 14x + 4 
Then we have to find (g o f)(x):
(g o f)(x) = [7(2x + 2) + 1] = (14x + 14 + 1) = 14x + 15 
Comparing both the results:

(g o f)(x) > (f o g)(x)
According to above explanation,
D.g(f(x)) produces the greatest output, is the correct answer.