Assuming no air resistance, all projectiles have:

a) constant vertical motion and accelerated horizontal motion.

b) constant vertical motion and constant horizontal motion.

c) accelerated vertical motion and constant horizontal motion.

d) accelerated vertical motion and accelerated horizontal motion.

Option C

C) accelerated vertical motion and constant horizontal motion.

Explanation:

If there is no air resistance then during the projectile movement the only force that causes an acceleration is the gravitational force.

We know that this force produces an acceleration of 9.8 m / s ^ 2 in the projectile.

As the gravitational force attracts the object towards the earth, then the acceleration that this force produces is always in the vertical direction. In the horizontal direction the object is not accelerated (because there is no air resistance).

Therefore the correct answer is option C.

 "accelerated vertical motion and constant horizontal motion".