Which of the following endocrine glands help in the regulation of physical growth, mental attainment and sexual maturity?

Answer: Option A

Option A: Pituitary gland
The pituitary gland is often called the "master gland" because it controls many other glands.
It secretes growth hormone, which is essential for physical growth.
It also influences sexual development and indirectly affects mental function.
So, this is a strong contender!

Option B: Thyroid gland
The thyroid gland mainly regulates metabolism.
While it's important for overall health and energy levels, its primary function isn't directly about growth, mental attainment and sexual maturity as the Pituitary gland.

Option C: Parathyroid gland
The parathyroid gland controls calcium levels in the blood.
Calcium is important for bone health and nerve function, but it doesn't have a major impact on growth, mental attainment and sexual maturity as the Pituitary gland.

Option D: Adrenal gland
The adrenal glands produce hormones that help the body respond to stress.
They also play a role in metabolism and immune function but don't directly regulate the main things mentioned in the question as the Pituitary gland.

Therefore, the correct answer is A: Pituitary gland. The Pituitary gland's influence on growth hormone and sexual development makes it the best fit for regulating all three areas mentioned in the question.