Let \( \Delta,\nabla \in \{\land,\lor\} \) be such that \( (p \to q)\,\Delta\,(p \nabla q) \) is a tautology. Then
\( \Delta=\land ,\ \nabla=\land \)
\( \Delta=\lor ,\ \nabla=\land \)
\( \Delta=\land ,\ \nabla=\lor \)
\( \Delta=\lor ,\ \nabla=\lor \)