Consider the following systems specification. If the transaction has an exclusive lock on the databa transaction has a shared lock on the database element, then it can read the element, but can not n shared lock on the database element. Let s be the proposition: "The transaction has a shared lock on the database element," e: "The tranWhich of the following are correct ways of determining if two compound propositions $p$ and $q$ are equivalent.

Construct a truth table for $(pq{)}^{{?}^{?}}(qp).$ If the proposition is tautology, then $p$ and $q$ are equivalent.

Construct a truth table for pharrq. If it is a tautology, then $p$ and $q$ are equivalent.

Construct a truth table for both of the compound propositions $p$ and $q.$ If the two are true in the same rows, then $p-=q.$

Construct a truth table for $pq.$ If it is a tautology, then $p$ and $q$ are equivalent.