In a TLS connection which key is used to decrypt messages after the handshake protocol has been completed:

The right approach will be "Symmetric key".

Explanation:

The whole last component of that same TLS handshake entails the development including its session key, which seems to be the main factor for network authentication which should currently be included. The "symmetric" session keys themselves, Therefore, symmetric keys are being used in a TLS connexon to decrypt messages because after a valid session procedure has indeed been accomplished.

The answer is b.
hope it’s