**Core Concept**
The optimal time for self-breast examination (SBE) is when the breast tissue is least glandular and most fatty, making it easier to detect abnormalities. This period is characterized by a decrease in progesterone levels, which can cause breast tenderness and swelling.

**Why the Correct Answer is Right**
The best time for SBE is 7-10 days after menses, when the progesterone levels are low. During this period, the breast tissue is less dense and more fatty, making it easier to palpate and detect abnormalities. This is also the time when the breast is least likely to be tender or swollen, allowing for a more accurate examination. The decrease in progesterone levels also makes the breast more responsive to hormonal changes, which can help in detecting any potential abnormalities.

**Why Each Wrong Option is Incorrect**
**Option A:** Premenstrual period is not the best time for SBE as the breast tissue is more glandular and dense, making it harder to detect abnormalities. Additionally, the breast is often tender and swollen due to the increase in progesterone levels.
**Option B:** During menses, the breast tissue is even more glandular and dense, making it difficult to perform an accurate examination. The breast is also often tender and swollen due to hormonal changes.
**Option D:** Ovulatory period is not the best time for SBE as the progesterone levels are high, causing breast tenderness and swelling. The breast tissue is also more glandular and dense, making it harder to detect abnormalities.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that SBE should be performed in a routine and consistent manner, ideally 7-10 days after menses, to become familiar with the normal breast anatomy and detect any potential abnormalities.

**✓ Correct Answer: C. 7-10 days after menses.**