Select the correct match for $X$ and $Y$:

Column $X$	Column $Y$
$(1)$ Attachment site of spindle fibers	$(P)$ Cell cycle
$(2)$ Pairing of homologous chromosomes	$(Q)$ Kinetochores
$(3)$ Exchange of genes	$(R)$ Synapsis
$(4)$ Interval between two successive cell divisions	$(S)$ Crossing over

• A
  $(1-P), (2-Q), (3-R), (4-S)$
• B
  $(1-Q), (2-P), (3-S), (4-R)$
• C
  $(1-Q), (2-R), (3-S), (4-P)$
• D
  $(1-S), (2-R), (3-P), (4-Q)$