Collin wants to solve this system of equations. Which number can he multiply the first equation by so that when the two equations are added together, the x term is eliminated?
1/2x + 1/4y = 5
2x + 3/8y = 5
A-4
B-2
C2
D4
1/2x + 1/4y = 5
2x + 3/8y = 5
A-4
B-2
C2
D4