Paramecia Live in Pond Water (A Hypotonic Environment)

Paramecia live in pond water (a hypotonic environment) .They have a structural feature,a contractile vacuole,that enables them to osmoregulate.If you observed paramecia in the following solutions,at which sucrose concentration would you expect the contractile vacuole to be most active?

A) 0) 0 mM sucrose
B) 0) 05 mM saline
C) 0) 08 mM sucrose
D) 1) 0 mM saline