Observation

Some candidates could not explain the terms. Some candidates gave vague answers generally related to breathing.
The expected answers are:

A. Vital capacity

is the maximum amount of air; a person can expel from the lungs; after a maximum/ normal inhalation/inspiration.  

 B. Tidal volume
can be described as the volume of air; that is inhaled/exhaled;within each respiratory  
cycle.                                                                   

 C. Residual volume
this can be described as the volume of air; remaining in the lungs; after a normal
expiration.