Epiphyseal plates are composed of the hyaline cartilage. It is present at the end of the long bones. The bones stops growing at early adulthood, due to the closure of epiphyseal plates.

Explanation:

The correct answer is option 'A' - Epiphyseal plates close after adolescence.

Epiphyseal plates:
- Epiphyseal plates, also known as growth plates, are areas of cartilage located at the ends of long bones.
- During childhood and adolescence, they are responsible for bone growth and elongation.
- As long as the epiphyseal plates are open, the bones can continue to grow in length.

Hypersecretion of Growth Hormone (GH):
- Hypersecretion of GH is a condition called acromegaly in adults.
- This occurs due to excessive production of GH by the pituitary gland.
- Acromegaly results in the enlargement of bones, soft tissues, and organs.

Reasons for no further increase in height:
1. Epiphyseal plates close after adolescence:
- During adolescence, the epiphyseal plates gradually close and are replaced by solid bone.
- Once the epiphyseal plates close, the bones can no longer grow in length.
- This closure usually occurs around the age of 18-20 in females and 20-22 in males.
- Therefore, even if there is hypersecretion of GH in adults, the bones cannot increase in height as the growth plates are no longer present.

2. Bones lose their sensitivity to Growth Hormone in adults:
- After the closure of the epiphyseal plates, the bones lose their sensitivity to GH.
- This means that even if there is an excess of GH in the body, it does not have any effect on bone growth or elongation.

3. Muscle fibers do not grow in size after birth:
- GH plays a role in the growth and development of muscle tissues.
- However, the growth of muscle fibers primarily occurs during childhood and adolescence.
- After reaching adulthood, the muscle fibers do not increase in size significantly.
- Therefore, hypersecretion of GH in adults does not lead to further growth or enlargement of muscle fibers.

4. Growth Hormone becomes inactive in adults:
- Growth Hormone does not become inactive in adults.
- It continues to have various functions in the body, such as regulating metabolism, promoting protein synthesis, and maintaining bone density.
- However, its role in bone growth and elongation is limited to the period when the epiphyseal plates are open.

Conclusion:
The hypersecretion of Growth Hormone in adults does not cause further increase in height because the epiphyseal plates close after adolescence. Once the growth plates are closed, the bones cannot grow in length, regardless of the amount of GH in the body.