Here are the answers of the following: 

(a) Surgical methods of contraception prevent gamete formation. - Corrected: They prevent fertilization or implantation, not gamete formation.

(b) All sexually transmitted diseases are completely curable. - Corrected: Not all STDs are curable; some, like HIV/AIDS, can only be managed.

(c) Oral pills are very popular contraceptives among rural women. - Corrected: Rural women mostly prefer sterilization or other local methods; oral pills are more common in urban areas.

(d) In Embryo Transfer (E.T.) techniques, embryos are always transferred into the uterus. - Corrected: Embryos are usually transferred to the uterus, but success depends on implantation and other factors.