Which activity causes the greatest risk of driving fatalities?
a. driving at night
b. drowsy driving
c. drinking and driving
d. driving with a passenger

The correct answer will be option-C

Explanation:

One of the measure cause of accidents on the roads is driving after drinking alcohol.

Drinking usually disturbs the skills required for driving like it reduces the focus of the driver, cause distraction in manipulating the situations and making a good judgement on the roads.

Drinking also causes to lose the interaction between the hand and foot and thus cause bad driving and sometimes result fatally to the driver.

Thus, Option-C is the correct answer.