What is the function of copper-T?
A. Checks mutation
B. Stops fertilization
C. Stops zygote formation
D. Stops obliteration of the blastocoel

Hint: An intrauterine contraceptive is fitted inside the uterus that helps in preventing pregnancy. It can be of two types; copper releasing and hormone-releasing. They help in preventing the most important fusion that results in the formation of a diploid organism. They are used for birth control and emergency contraception.

Complete answer:
IUDs or Intrauterine devices prevent fertilization or implantation in women. The copper intrauterine device is a T-shaped plastic copper device that releases a trace amount of copper into the uterine region. They are commonly used as an emergency contraceptive method instead of contraceptive pills. It is effective in preventing pregnancy up to 99% and can also last up to five to ten years. It has a fine nylon string which is attached to the copper-T that comes out through the cervix. They prevent sperm and egg fusion and also change the lining of the uterus. The changes in the uterine lining make it difficult for a fertilized egg to the implant to start the pregnancy. Side effects of IUDs include heavy menstrual periods, painful periods, or the device may come out. It is less recommended in people at high risk of sexually transmitted infections as it may increase the risk of pelvic inflammatory disease in the first three weeks after insertion.
Hence, the correct answer is option B.

Note: It acts as a spermicide and the presence of copper increases the level of copper ions, lymphocytes, and prostaglandins within the uterine and tubal fluids. It cannot prevent a person from sexually transmitted diseases (STDs). It is one of the types of contraception methods.