Select the correctly mathched pair.

Explanation

To solve the question of selecting the correctly matched pair, we will analyze each option provided.

### Step-by-Step Solution:

1. **Analyze the First Option: Pineal Gland and Menstrual Cycle**
- The pineal gland is known to secrete melatonin.
- Melatonin plays a role in regulating the sleep-wake cycle and can influence the menstrual cycle.
- Therefore, this statement is **incorrect** because the pineal gland does influence the menstrual cycle.

2. **Analyze the Second Option: Corpus Luteum and Oxytocin**
- The corpus luteum is a structure in the ovary that forms after ovulation.
- It primarily secretes progesterone, which is essential for maintaining the uterine lining.
- It does not secrete oxytocin; hence, this statement is **incorrect**.

3. **Analyze the Third Option: Interstitial Cells and Erythropoiesis**
- Interstitial cells, also known as Leydig cells, are located in the testes.
- They are responsible for the secretion of androgens (like testosterone) under the influence of LH (Luteinizing Hormone).
- They are not involved in erythropoiesis (the production of red blood cells). Thus, this statement is also **incorrect**.

4. **Analyze the Fourth Option: Cholecystokinin and Pancreatic Enzyme Secretion**
- Cholecystokinin (CCK) is a hormone that stimulates the secretion of digestive enzymes from the pancreas.
- It acts on the acinar cells of the pancreas, promoting the release of enzymes necessary for digestion.
- Therefore, this statement is **correct**.

### Conclusion:
The correctly matched pair is the fourth option: **Cholecystokinin stimulates pancreatic enzyme secretions.**