Is primarily celebrated in the united states and

D.) helping seniors

Explanation:

Volunteering Is freely offering to do something without expecting anything in return.

A.) running for political office is not volunteering. You run for political office with the goal of getting into office. You are not freely offering help.

B.) paying taxes is not volunteering, because paying taxes is mandatory in accordance to government law.

C.) joining the military (in this case) is not volunteering, you are not freely offering your help. You get paid, and gain benefits.

D.) helping seniors is volunteering. You are freely offering your help to the elderly without expecting payment.