Given the following sets.
A = {0, 1, 2, 3}
B = {a, b, c, d}
C = {0, a, 2, b}

Find A∩B.
1 2 3 or 4

1 {0, 1, 2, 3}

2 {a, b, c, d}

3 {0, a, 2, b}

4 empty set {0, a}