Which one is the cofactor of carbonic anhydrase?

Which of the following is a co-enzyme?

Which of the following enzymes are activated in the presence of $Mg^{++}$?
$(A)$ Pyruvate dehydrogenase
$(B)$ $DNA$ polymerase
$(C)$ Hexokinase
$(D)$ Rubisco
$(E)$ Catalase
$(F)$ $PEP$ carboxylase
$(G)$ Amylase
Options:
$(a)$ $B, C, D, E$
$(b)$ $A, F, C, D$
$(c)$ $G, F, B, E$
$(d)$ $A, F, C, B$

Assertion : $A$ co-enzyme or metal ion that is very tightly bound to enzyme protein is called a prosthetic group.
Reason : $A$ complete,catalytically active enzyme together with its bound prosthetic group is called an apoenzyme.

Substances which enhance reactions after combining with enzymes are called

Pantothenic acid and biotin are associated with which of the following?