The answer is B. P waves.
I took the test and it was correct. I hope this helps!
Pressure is a force per unit area.
Answer:

Explanation:
The normal force exerted on the car by the walls of the cylinder at the bottom of the vertical circle will be such that when substracted to the weight it must give the centripetal force, since at that point on the vertical 
We also know that the equation for the centripetal force is:

Mixing both equations we get:


Which for our values means:

The answer is <span>A) Velocity describes speed with direction.
Speed can be in any direction </span>