Match List - I with List - II and choose the correct answer.

List - I	List - II
(a) Vaults	(i) Entry of sperm through Cervix is blocked
(b) IUDs	(ii) Removal of Vas deferens
(c) Vasectomy	(iii) Phagocytosis of sperms within the Uterus
(d) Tubectomy	(iv) Removal of fallopian tube

To find the correct match between List - I and List - II, let us analyze each contraceptive method listed in List - I and connect it to its correct mechanism or description in List - II:

(a) Vaults: Vaults are hemispherical rubber domes that are inserted into the female reproductive tract to cover the cervix during coitus. They act as physical barriers that block the entry of sperms through the cervix. Therefore, (a) matches with (i).

(b) IUDs (Intrauterine Devices): Intrauterine devices are inserted by doctors or expert nurses in the uterus through the vagina. These devices increase the phagocytosis of sperms within the uterus, reducing sperm motility and their fertilizing capacity. Therefore, (b) matches with (iii).

(c) Vasectomy: Vasectomy is a surgical method of sterilization in males where a small part of the vas deferens is removed or tied up through a small incision on the scrotum. This prevents the transport of sperm. Therefore, (c) matches with (ii).

(d) Tubectomy: Tubectomy is a surgical sterilization method in females where a small part of the fallopian tube is removed or tied up through a small incision in the abdomen or through the vagina. Therefore, (d) matches with (iv).

Combining all the correct matches:
a - (i)
b - (iii)
c - (ii)
d - (iv)

Thus, the correct option is a - (i) b - (iii) c - (ii) d - (iv).