Under which of the following conditions are you most likely to fall sick?

(a) when you are taking examinations.

(b) when you have travelled by bus and train for two days.

(c) when your friend is suffering from measles. Why?

A person can most likely fall sick when his/her friend is suffering from measles. It can easily be transferred through air and respiration. It is always better to stay away from your friend who is affected with measles else even you will get infected with the disease.