Which among the following is not the function of testes at puberty?
(i) Formation of germ cells (ii) Secretion of testosterone
(iii) Development of placenta (iv) Secretion of estrogen

Options

A. (i) and (ii)
B. (ii) and (iii)
C. (iii) and (iv)
D. (i) and (iv)

Explanation

To solve the question "Which among the following is not the function of testes at puberty?", we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding the Role of Testes**:
- The testes are the male reproductive organs responsible for two main functions: the production of sperm (germ cells) and the secretion of male sex hormones, primarily testosterone.

2. **Analyzing Each Option**:
- **Option (i): Formation of germ cells**:
- This is a function of the testes. The testes produce sperm, which are male germ cells.
- **Conclusion**: This option is a function of the testes.

- **Option (ii): Secretion of testosterone**:
- This is also a function of the testes. The testes secrete testosterone, which is crucial for the development of male secondary sexual characteristics.
- **Conclusion**: This option is a function of the testes.

- **Option (iii): Development of placenta**:
- The placenta develops in females during pregnancy and is not related to the function of the testes. The testes do not play any role in the development of the placenta.
- **Conclusion**: This option is NOT a function of the testes.

- **Option (iv): Secretion of estrogen**:
- Estrogen is primarily a female sex hormone, and while males do have small amounts of estrogen, it is not secreted by the testes in significant amounts. The primary hormones secreted by the testes are androgens like testosterone.
- **Conclusion**: This option is NOT a function of the testes.

3. **Final Answer**:
- The question asks for which option is NOT a function of the testes at puberty. Based on our analysis, both options (iii) and (iv) are not functions of the testes. However, since the question asks for one option, the most clear answer is:
- **Option (iii): Development of placenta**.