Which of the following methods of contraception has the maximum chances of failure?

Identify the odd one out.

What are the advantages of natural methods of contraception over artificial methods?

Vasectomy has no effect on the sexual life of a male because:

Which of the following have been found to be very effective as emergency contraceptives,as they could be used to avoid possible pregnancy due to rape or casual unprotected intercourse if administered within $72$ hours?
$A.$ Administration of progestogens
$B.$ Progestogen-estrogen combinations
$C.$ $IUDs$ inserted within $72$ hours of coitus

How do diaphragms,cervical caps,and vaults function as contraceptives?