The number of elements in the power set of the set {{A, B}, C} is
No of elements of power set will be $2^{n}$ . here n is element of set
so given set has 2 elements then power set has $2^{2}$ = 4 elements(Ans option d)
which are { $\phi$ , {A,B}, {C}, { { A,B},C} }
TWO ELEMENTS SO NUMBER ELEMENTS =2^2=4
{ ∅, {{A,B}}, {C}, {{A,B},C} }