**Core Concept**
Endocervical polyps are benign growths that arise from the mucosal lining of the cervix. They are often associated with hormonal changes, particularly during the menstrual cycle, which can lead to symptoms.

**Why the Correct Answer is Right**
The classical symptom of endocervical polyps is intermenstrual bleeding, which occurs between two menstrual periods. This is because endocervical polyps can cause irregular shedding of the cervical mucosa, leading to bleeding. The bleeding can be light or heavy and may be accompanied by a foul odor. The bleeding is often anovulatory, meaning it is not related to ovulation, and can be a sign of underlying hormonal imbalance. The exact mechanism is not fully understood, but it is thought to be related to the increased levels of estrogen during the menstrual cycle, which can stimulate the growth of endocervical polyps.

**Why Each Wrong Option is Incorrect**
**Option A:** Cervical prolapse is a condition where the cervix or uterus slips out of its normal position, causing symptoms such as pelvic pressure, back pain, and difficulty urinating. It is not directly related to endocervical polyps.

**Option B:** Dyspareunia, or painful intercourse, can be caused by a variety of factors, including vaginal dryness, vaginal infections, and pelvic pain. While endocervical polyps may cause discomfort or pain during intercourse, it is not the most classical symptom associated with these growths.

**Option D:** Dysmenorrhea, or painful menstruation, is a common symptom of several conditions, including endometriosis, adenomyosis, and uterine fibroids. While endocervical polyps may cause some discomfort during menstruation, it is not typically associated with dysmenorrhea.

**Clinical Pearl / High-Yield Fact**
Endocervical polyps are often asymptomatic and may be discovered incidentally during a routine pelvic exam. However, when symptoms do occur, they are often related to intermenstrual bleeding, which can be a sign of underlying hormonal imbalance.

**✓ Correct Answer: C. Intermenstrual bleeding**