Correct Answer: A
Session affinity provides a best-effort attempt to send requests from a particular client to the same backend for as long as the backend is healthy and has the capacity, according to the configured balancing mode.
It is the best way to assure that session data is maintained in memory.
It is a feature of the HTTP(S) load balancing.
Google Cloud SSL Proxy Load Balancing terminates user SSL (TLS) connections at the load balancing layer, then balances the connections across your instances using the SSL or TCP protocols. Cloud SSL proxy is intended for non-HTTP(S) traffic. For HTTP(S) traffic, HTTP(S) load balancing is recommended instead.
pass-through load balancer, so your backends receive the original client request