7. What is the cardinality of each of the following sets?a) { }b) { { } }c) {a, {a}, {a, {a}} }NOTE: I need the answer type out NOT hand written, the last person to answer this question teriibly hand wrote the answer and I could not read it.

Answer:  The cardinality of set (a) is 0,the cardinality of set (b) is 1andthe cardinality of set (c) is 3. Step-by-step explanation:  We are given to find the cardinality of each of the following sets :(a) { }.(b) { { } }.(c) {a, {a}, {a, {a}} }.We know thatCARDINALITY of a set is the number of elements present in the set.(a) The given set is A = { }.The set A is an empty set, so it does not contain any element. Hence, the cardinality of the set A is 0.(b) The given set is B = { { } }.The set is B is singleton set, contains only one element (that is empty set). So, the cardinality of the set B is 1.(c) The given set is C = {a, {a}, {a, {a}} }.The set C has three elements, a, the set {a} and the set {a, {a}}. So,  the the cardinality of set C is 3.Thus,the cardinality of set (a) is 0,the cardinality of set (b) is 1andthe cardinality of set (c) is 3.