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.
-P ⊃ (Q ⊃ R) ⊃ [(P • ∼R) ⊃ ∼Q]

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