Let Δ, ∇ ∈{∧, } be such that p ∇ q ⇒((p Δ q) ∇ r) is a tautology. Then (p ∇ q) Δ r is logically equivalent to:

Let $\displaystyle \Delta, \nabla \in\{\wedge, \vee\}$ be such that $\displaystyle p \nabla q \Rightarrow((p \Delta q) \nabla r)$ is a tautology. Then $\displaystyle (p \nabla q) \Delta r$ is logically equivalent to :