Rachel, David, and Kristen decide to pool their money to buy a video game system. David contributes 4 dollars more than twice what Kristen does, and Kristen contributes 3 dollars less than Rachel does. If Rachel contributes r dollars, then, in terms of r, how much does David contribute?

a. (r - 7)/2

b. (r - 2)/7

c. (2r + 7)/2

d. 2r − 2

e. 2r + 7