Let \( \Delta \in \{\land, \lor, \Rightarrow, \Leftrightarrow\} \) be such that \( (p \land q)\ \Delta\ \big((p \lor q) \Rightarrow q\big) \) is a tautology. Then \( \Delta \) is equal to:
\( \land \)
\( \lor \)
\( \Rightarrow \)
\( \Leftrightarrow \)