Explanation:

- Option 1: Polygamy was allowed

- In the Vedic age, polygamy was indeed permitted. It was socially acceptable, though not widespread among all classes.

- Option 2: Child marriage became prominent

- Child marriage was not a feature of the early Vedic period. It became more common in later eras due to social and cultural changes.

- Option 3: Widows could remarry

- Widow remarriage was allowed in the Vedic age. Women had some social freedom, and remarriage was a possibility.

- Option 4: Both (a) and (c)

- This option correctly points out that both polygamy was allowed and widows could remarry.