For Each of the Following Questions, Determine Whether the Given $\lor$

For each of the following questions, determine whether the given formula is a wff or not. If it is a wff, indicate its main operator.
-[(W ⊃ X) • (Y $\lor$ ∼X) ] ≡ [∼(Z $\lor$ Y) ⊃ ∼W]

A) It's a wff. The main operator is the •.
B) It's a wff. The main operator is the ≡.
C) It's a wff. The main operator is the first ∼, reading left to right.
D) It's a wff. The main operator is the second ⊃, reading left to right.
E) Not a wff