Centrifugal force increases with
a. deceleration
b. traction
c. acceleration
d. all of the above

Option (C) Acceleration

Explanation:
Centrifugal force is the fictitious force that we feel while moving in the circular path. Fictitious in a sense that it does not really exist, but we feel it in a non-inertial coordinate system.

Fc = 
where Fc = centrifugal force,
m = mass,
v = speed,
r = radius

If a body is acceleration, it means that its velocity is increasing. According to the equation of Centrifugal force mentioned above, Centrifugal force is directly porportional to the square of the velocity of a body. Hence, when the velocity increases (meaning there is an acceleration), the centrifugal force also increases (due to its direct relationship with the velocity of the object).

The rocks expand when there hot/warm  and contract when they are cold.