Answer: B.

Step-by-step explanation:
When we talk about projectile motion, we have to deal with parabolic motion, which has two components: vertical and horizontal.
In the case of Earth, the acceleration is due gravity, which is constant and directed downwards (vertically) and have a value of
.
Now, in the case of the horizontal component, the acceleration will always be zero.
This is because we are dealing with parabolic movement, the x-component of the velocity remains the same (hence, there is no acceleration), while the y-component always change because it is affected by the acceleration due gravity that acts verticaly.