Explanation:

- The father was 29 years old before marriage.

- The mother was 26 years old before marriage (since the father is 3 years older).

- They married after 3 years, making the father 32 and the mother 29 at the time of marriage.

- We don't know when the child was born after marriage, but the average age of the couple when their son was born was 35.

- At the time of the son’s birth, the combined age of the couple was 70 (35 years each on average).

- If the father was 32 at marriage, he and his wife’s combined age increased by 70 - 61 = 9 more years after marriage.

- This means the child was born 4 years 6 months after marriage.

The correct answer is Option 1: 4 years 6 months.