It is given that A is the set of natural numbers.
Natural numbers are numbers including the positive integers from 1 to infinity.
Natural numbers exclude zero and negative integers.
So, set A can be expressed as:
A={1,2,3, 4....∞}
It is given B⊆A. It means that B is the subset of A.
So, only the elements of set A can be there in set B. Set B does not include elements that are not in set A.
So, among the given options, the set B is B={1,2,3,4}.
