Explanation:

- Joking relationships are special social interactions involving playful teasing, mock insults, or banter without causing offense.

- Option 1: Husband and wife

- ?? Usually, marital relationships are expected to be respectful and formal in many traditional societies, not a classic example of structured joking relationships as defined in anthropology.

- Option 2: Mother and daughter

- Generally, this bond involves care and guidance rather than ritualized joking.

- Option 3: Father and son

- Typically, their relationship is seen as nurturing or disciplinary, not commonly as formalized joking.

- Option 4: Brother-in-law and sister-in-law

- In many cultures, especially in South Asia and Africa, this is a classic example. Here, playful teasing is culturally encouraged and expected.

- Correct Answer: Option 4 – brother-in-law and sister-in-law.