Which one of the following is not a social skill among children?

Correct Answer: Distribution of birthday sweets

Showing affection to a friend, sharing food with peers, and playing with other children are social skills because they involve interpersonal interaction, cooperation, communication, and relationship-building.

Distribution of birthday sweets is mostly a customary or cultural act. It may happen in a social setting, but it is not itself a core social skill among children.

Therefore, the correct answer is option D.