Start by taking the information we know, and write equations to represent the realationships:
1) "1/8 lbs less flour to make bread than to make cookies"

2) "1/4 lb more flour to make cookies than to make brownies:

3) "she used 1/2 lb of flour ro make bread"

From here you can solve for

using back substitution.
The empty jug weighs 0.75 lb
With the 3c, the total weighs 2.25 lb. That means:
3c + empty jug = 3c + 0.75 = 2.25
3c = 2.25 - 0.75
3c = 1.5
and 1c = 0.5 (so c is a constant -or the slope-)
Then the equation is:
y = 0.5x + 0.75
The answer is d, have a good day