Final answer:
The correct option is B). Menstruation is the primary sexual characteristic among the given options, as it is directly related to the reproductive process in females.
Step-by-step explanation:
To answer the question regarding which option is a primary sexual characteristic, it's important to understand the distinction between primary and secondary sexual characteristics. Primary sexual characteristics are those directly involved in reproduction, which would include the uterus and ovaries in females and testes in males. In contrast, secondary sexual characteristics refer to the features that emerge during puberty but are not directly involved in the reproductive process, such as breast development, the growth of body hair, and changes in voice and skin.
Given the options provided:
- a) breast development
- b) menstruation
- c) body hair development
- d) skin changes
Menstruation (Option b) is the primary sexual characteristic, as it is part of the reproductive process in females.