Let A, B and C be three sets and suppose there is an element belonging to A ⋂ B ⋂ C. Then it it's necessarily true that:

A. A ∪ B ∪ C is contained in A ∪ B
B. There is an element that is in A ⋂ B but not in C
C. A ⋂ B is strictly contained in A ⋂ B ⋂ C
D. A ⋂ B ⋂ C is strictly contained in A ⋂ B
E. A ⋂ B is not the empty set