Answer:
a
Explanation:
Direct proportion is when two numbers move in the same direction. If one of the numbers increase, the other number increases and if the one of the numbers decrease, the other number decreases. The magnitude of the movement of the numbers is bounded by a constant
The expression for direct proportion is
y ∝ kx
where k is the constant
let illustrate with an example :
If x = 10
k = 4
y = 10 x4 = 40