Select the correct option for the following statements:
$(i)$ $A$ chromosome in which the centromere is situated near the middle is called a metacentric / submetacentric chromosome.
$(ii)$ The air vacuole / contractile vacuole helps in osmoregulation.

• A
  $(i)$ Metacentric,$(ii)$ Air vacuole
• B
  $(i)$ Submetacentric,$(ii)$ Contractile vacuole
• C
  $(i)$ Metacentric,$(ii)$ Contractile vacuole
• D
  $(i)$ Submetacentric,$(ii)$ Air vacuole