**Core Concept**
The process of ovulation involves the release of a mature oocyte from the ovarian follicle, accompanied by the surrounding layer of granulosa cells. This process is a crucial aspect of the female reproductive cycle.

**Why the Correct Answer is Right**
After ovulation, the discharged oocytes and surrounding layer of granulosa cells are collectively referred to as the corpus luteum, which plays a vital role in producing progesterone hormone to prepare the endometrium for a potential pregnancy. The corpus luteum forms in the ovulatory fossa of the ovary, where the ruptured follicle is located. The granulosa cells in the corpus luteum differentiate into lutein cells, which produce progesterone, while the oocyte degenerates and is reabsorbed.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the post-ovulatory structure formed by the discharged oocytes and granulosa cells.
**Option B:** This option is incorrect because it is a term used to describe the pre-ovulatory follicle, not the post-ovulatory structure formed by the discharged oocytes and granulosa cells.
**Option C:** This option is incorrect because it is a term used to describe the follicular fluid, not the post-ovulatory structure formed by the discharged oocytes and granulosa cells.

**Clinical Pearl / High-Yield Fact**
The corpus luteum is a temporary endocrine structure that plays a crucial role in preparing the endometrium for a potential pregnancy. Its formation and function are essential for maintaining the early stages of pregnancy.

**Correct Answer: C. Corpus luteum.**