Under which one of the following conditions should you avoid using hydrotherapy equipment?
a. you are overweight or obese.
b. you do not know how to swim.
c. you don t have previous experience using the equipment.
d. you have a heart condition.

You should avoid using hydrotherapy equipment if you have a heart condition. Correct D

Hydrotherapy is  a type of physiotherapy for treating  pain and certain ailments using warm water.  However, the hydrostatic pressure increases the venous return and this is dangerous for individuals with heart conditions.