As a Projectile Moves Along Its Parabolic Trajectory, Which of the Following

Multiple Choice

As a projectile moves along its parabolic trajectory, which of the following remain constant (ignoring air resistance, and defining the $z$ axis as pointing upward) ?

A) Its speed
B) Its velocity
C) Its $x$ -velocity and $y$ -velocity
D) Its $z$ -velocity
E) Its acceleration
F) Its $x$ -velocity, $y$ -velocity, and acceleration
$\mathrm{T}$ . Some other combination of the given quantities