Mathematics

Problem

Let

S = \lnot\bigl(p \land (q \lor r)\bigr)

. Which one of the following statements is logically equivalent to

S

? a)

\lnot p \land \lnot q \land \lnot r

(\lnot p \land \lnot q) \lor r

\lnot p \lor (\lnot q \land \lnot r)

\lnot p \lor \lnot q \lor \lnot r