Smith married 21 years ago at the age of 90 years. His wife's present age 99 years. If 24 years later the average age of Smith, his wife and their son was 90 years, then what is son's present age?

(A) 12 Years
(B) 13 Years
(C) 14 Years
(D) 15 Years

Smith married 21 years ago at the age of 90 years. His wife’s present age 99 years. If 24 years later the average age of Smith, his wife and their son was 90 years, then what is son’s present age?