Test tube baby programme employs zygote intrafallopian transfer (ZIFT) technique. In this technique fusion of ovum and sperms is done outside the body of woman to form zygote which is allowed to divide forming 8 blastomeres, then it is transfered the fallopian tube of the woman.

The correct answer is option 'D' - Zygote intra-fallopian transfer (ZIFT).

Explanation:

The test-tube baby programme, also known as in vitro fertilization (IVF), is a technique used to help couples with infertility issues to conceive a child. It involves the fertilization of an egg with sperm outside the woman's body, in a laboratory dish, and then transferring the resulting embryo into the woman's uterus.

Zygote intra-fallopian transfer (ZIFT) is one of the techniques used in the test-tube baby programme. Let's understand what ZIFT involves and why it is the correct answer:

1. Zygote Intra-Fallopian Transfer (ZIFT):
- ZIFT is a type of assisted reproductive technology (ART) that combines elements of both in vitro fertilization (IVF) and gamete intra-fallopian transfer (GIFT).
- It involves the retrieval of eggs from the woman's ovaries, fertilization of the eggs with sperm in a laboratory dish to form embryos, and then transferring the resulting zygotes (fertilized eggs) into the fallopian tubes instead of the uterus.
- The zygotes are transferred to the fallopian tubes using a laparoscopic procedure, where a small incision is made in the woman's abdomen to access the fallopian tubes.
- The zygotes then travel through the fallopian tubes and into the uterus, where they implant and develop into a pregnancy.

Reasons why ZIFT is the correct answer:

1. Gamete intra-fallopian transfer (GIFT):
- GIFT is a technique where unfertilized eggs and sperm are directly transferred into the woman's fallopian tubes.
- Unlike ZIFT, GIFT does not involve the creation of embryos in a laboratory dish.
- Therefore, GIFT does not fall under the test-tube baby programme, as mentioned in the question.

2. Intra-cytoplasmic sperm injection (ICSI):
- ICSI is a technique where a single sperm is directly injected into an egg to achieve fertilization.
- Although ICSI is commonly used in the test-tube baby programme, it does not involve the transfer of embryos into the fallopian tubes.
- Therefore, ICSI is not the correct answer for this question.

3. Intra-uterine insemination (IUI):
- IUI is a procedure where washed and concentrated sperm are directly placed into a woman's uterus around the time of ovulation.
- IUI does not involve the creation of embryos or the transfer of zygotes into the fallopian tubes.
- Therefore, IUI is not the correct answer for this question.

In conclusion, the correct technique employed by the test-tube baby programme is Zygote intra-fallopian transfer (ZIFT).