**Core Concept**
The process of ovulation involves the maturation and release of a mature oocyte from the ovarian follicle. This process is accompanied by the extrusion of the first polar body, which is a critical event in oogenesis.

**Why the Correct Answer is Right**
During oogenesis, the primary oocyte undergoes two meiotic divisions: meiosis I and meiosis II. The first meiotic division results in the extrusion of the first polar body, which contains one haploid set of chromosomes. This event occurs before the oocyte is released from the follicle. In a typical menstrual cycle, ovulation occurs around the 14th day, and the first polar body is extruded shortly before the oocyte is released.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the first polar body is extruded during meiosis I, not meiosis II. Meiosis II is the second division of meiosis, which occurs after the oocyte has been released from the follicle.
**Option B:** This option is incorrect because it suggests that the first polar body is extruded after the oocyte has been released from the follicle. However, the first polar body is extruded before ovulation, during meiosis I.
**Option C:** This option is incorrect because it suggests that the first polar body is extruded during the menstrual phase of the cycle. However, the first polar body is extruded during the follicular phase, before ovulation.

**Clinical Pearl / High-Yield Fact**
The extrusion of the first polar body is a critical event in oogenesis, and it marks the beginning of the second meiotic division. This process is essential for the production of mature oocytes, which are released from the follicle during ovulation.

**Correct Answer:** B. During meiosis I, shortly before ovulation.