Q. Correct regarding the use of vaginal diaphragm is….

(a) Introduce it just before ejaculation and remove it after ejaculation
(b) Addition of spermicidal jelly has no proved effect on its effectiveness
(c) It should be introduced up to 3 hours before intercourse and is to be kept for at least 6 hours after the coital act
(d) It should be introduced up to 3 hours before intercourse and should be removed immediately after ejaculation