Consider the satisfiability and validity properties of propositional logic statements. Which of the following

statements is definitely true?

Both satisfiability and validity can be performed in polynomial time.

Both satisfiability and validity are NP$-$Complete.

Checking satisfiability is NP$-$Complete $($requires exponential time$),$ while checking validity can be done in

polynomial time.

Checking validity is NP$-$Complete while checking satisfiability can be done in polynomial time.