Select the mismatch w.r.t function of contraceptives.

Answer

To solve the question regarding the mismatch with respect to the function of contraceptives, we will analyze each option provided in the context of their functions.

### Step-by-Step Solution:

1. **Understanding Contraceptives**:
- Contraceptives are methods used to prevent or delay pregnancy. They can be hormonal, barrier, or surgical methods.

2. **Analyzing Option A - Oral Contraceptive Pills**:
- Oral contraceptive pills contain hormones (progesterone and/or estrogen). Their primary function is to prevent ovulation and create an unfavorable environment for implantation in the uterus.
- **Conclusion**: This option correctly matches the function of oral contraceptive pills.

3. **Analyzing Option B - Barrier Method Preventing Lactation**:
- Barrier methods, such as condoms, physically prevent sperm from reaching the egg. They do not have any role in lactation, which is the production of milk after childbirth.
- **Conclusion**: This option is a mismatch because barrier methods do not prevent lactation.

4. **Analyzing Option C - Vasectomy**:
- Vasectomy is a surgical procedure for males where the vas deferens is cut to prevent sperm from being released during ejaculation. This effectively stops the transport of sperm.
- **Conclusion**: This option correctly matches the function of vasectomy.

5. **Analyzing Option D - Tubectomy**:
- Tubectomy is a surgical procedure for females where the fallopian tubes are cut to prevent the egg from being fertilized by sperm. This is also a permanent method of contraception.
- **Conclusion**: This option correctly matches the function of tubectomy.

6. **Final Conclusion**:
- The only incorrect match is Option B, which states that the barrier method prevents lactation. Therefore, the answer to the question is Option B.