Answer: B
let A be any set, then the set of all subsets of A is called power set of A
To understand this question better let’s try to understand it with another example
A = { }
P(A) = {Ф}
A = {a}
P(A) = {Ф, {a}}
A = {a, b}
P(A) = {Ф, {a}, {b}, {a, b}}
A = {Ф}
P(A) = {Ф, {Ф}}