Given the two sets, which statement is true?

А = {1, 2}

В = {1, 2, 3, 4}

B C A

3 C A

4 C A

A C B

none of the above

A⊆B

Step-by-step explanation:

C⊆D if the set C contains only elements from set D.

Let's look at the first choice:

B⊆A is not true because 3 and 4 are not in A.

Second choice:

3⊆A is not true because 3 is not a set; it is an element.

Also, 3 is not even in {1,2}.

Third choice:

See explanation for choice 2.

Fourth choice:

A⊆B is true because all the elements in A are contained in B.

That is the elements 1 and 2 are contained in the set {1,2,3,4} which is B.