In symmetric key distribution using symmetric encryption, which one of the following options is preferable to use for end$-$to$-$end encryption over a network?

Group of answer choices

If A and B have previously and recently used a key, one party could transmit the new key to the other, using the old key to encrypt the new key.

A key could be selected by party A and physically delivered to party B$.$

A third party could select the key and physically deliver it to parties A and B$.$

If A and B each have an encrypted connection to a third$-$party C$,$ C could deliver a key on the encrypted links to A and B$.$