Match the columns.

Column $-I$	Column $-II$
$(a)$ Parturition	$(p)$ Attachment of embryo to endometrium
$(b)$ Gestation	$(q)$ Release of egg from Graafian follicle
$(c)$ Ovulation	$(r)$ Delivery of Foetus from uterus
$(d)$ Implantation	$(s)$ Duration between pregnancy and birth
	$(t)$ Formation of zygote by fusion of egg and sperm

• A
  $a-q, b-s, c-p, d-t$
• B
  $a-r, b-q, c-s, d-p$
• C
  $a-t, b-p, c-q, d-r$
• D
  $a-r, b-s, c-q, d-p$