Proposition 2B Given the Following Proposition

Multiple Choice

Proposition 2B
Given the following proposition:
[(A ⊃ Y) ≡ (B ⊃ ∼X) ] ∨ ∼[(B • ∼ X) ≡ (Y • A) ]
-In Proposition 2B, the main operator is a:

A) Horseshoe.
B) Dot.
C) Tilde.
D) Wedge.
E) Triple bar.