Ovulation is triggered by the increase of

Options

A. Estrogen
B. Progesterone
C. FSH
D. LH

Answer

### Step-by-Step Solution:

1. **Understanding Ovulation**:
- Ovulation is the process where a mature ovum (egg) is released from the Graafian follicle in the ovary. This typically occurs around the 14th day of the menstrual cycle.

2. **Identifying Hormones Involved**:
- The question asks which hormone's increase triggers ovulation. The four hormones to consider are Estrogen, Progesterone, Follicle Stimulating Hormone (FSH), and Luteinizing Hormone (LH).

3. **Analyzing Each Hormone**:
- **Estrogen**:
- While estrogen levels rise around the time of ovulation, it does not directly trigger the process of ovulation. Its role is more about regulating the menstrual cycle and promoting secondary sexual characteristics.
- **Progesterone**:
- Progesterone levels also increase after ovulation to maintain the endometrial lining for potential pregnancy, but it does not trigger ovulation itself.
- **Follicle Stimulating Hormone (FSH)**:
- FSH is important for the growth and maturation of ovarian follicles but does not directly cause ovulation.
- **Luteinizing Hormone (LH)**:
- LH is crucial for ovulation. A surge in LH levels around the 14th day of the menstrual cycle leads to the rupture of the Graafian follicle, releasing the ovum.

4. **Conclusion**:
- The hormone that triggers ovulation is **Luteinizing Hormone (LH)**. Therefore, the correct answer is option D.