Proposition 1E Given the Following Proposition

Multiple Choice

Proposition 1E
Given the following proposition:
∼{[(Y ≡ ∼ A) ⊃ (∼ X ∨ Y) ] • (∼ B ∨ ∼ X) }
-In Proposition 1E, the main operator is a:

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