Explanation:

- Asura Vivaha: This is one of the eight types of Hindu marriages, where the groom gives money or gifts to the bride and her family. It is not related to social status or caste hierarchy.

- Hypergamy: This means marrying "up" in the social or caste hierarchy (for example, a girl from a lower caste marrying a boy from a higher caste).

- Prajapatya Vivaha: Also one of the eight types of marriages in Hindu tradition where the couple, together, seek to perform their religious duties. It is not related to the concept of marrying up or down in caste.

- Hypogamy: This means marrying "down" in social or caste hierarchy (for example, a girl from a higher caste marrying a boy from a lower caste).

A Brahmin girl (higher caste) marrying a Kshatriya boy (lower than Brahmin) is an example of Hypogamy.

Correct Answer: Option 4- Hypogamy