A person 70 to 79 years old

A. Nonagenarian

B. Centenarian

C. Octogenarian

D. Septuagenarian

Answer: Option D

Solution(By Examveda Team)

One word substitute is Septuagenarian.

Nonagenarian: a person who is between 90 and 99 years old.
Centenarian: a person who is a hundred or more years old.
Octogenarian: a person who is between 80 and 89 years old.
Septuagenarian: a person who is between 70 and 79 years old.