Which of the following is mechanical barrier used in birth control ?

Options

A. Copper-T
B. Diaphragm
C. Loop
D. Dalcon shield.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a mechanical barrier used in birth control. Mechanical barriers are contraceptive methods that physically block sperm from reaching the egg.

2. **Identifying the Options**: The options given are:
- Copper tube
- Diaphragm
- Loop
- Talcum sheet

3. **Analyzing Each Option**:
- **Copper tube**: This is typically associated with intrauterine devices (IUDs) and not a mechanical barrier.
- **Diaphragm**: This is a cup-like structure made of rubber that is inserted into the vagina to cover the cervix and prevent sperm from entering the uterus. It is indeed a mechanical barrier.
- **Loop**: This refers to a type of IUD, which is also not a mechanical barrier but rather a device placed inside the uterus.
- **Talcum sheet**: This is not a recognized method of birth control and does not serve as a mechanical barrier.

4. **Conclusion**: The only option that qualifies as a mechanical barrier is the **diaphragm**. It is designed to prevent sperm from entering the uterus and is used by women.

5. **Final Answer**: The correct answer is **Diaphragm**.