Explanation:

- Initially, the average age of the man and wife at marriage was 27 years, making their combined age 54 years.

- After 4 years, their combined age increases by 8 years (4 years each).

- This would make their current ages 62 years (54 + 8).

- They have a one-year-old child, adding another year for the child.

- Now, the total age of the family (man, wife, and child) is 63 years.

- The family consists of three people, so the average age is \( \frac{63}{3} = 21 \) years.

The correct option is 21 years.