A User Has Configured ELB with a TCP Listener at ELB

Multiple Choice

A user has configured ELB with a TCP listener at ELB as well as on the back-end instances. The user wants to enable a proxy protocol to capture the source and destination IP information in the header. Which of the below mentioned statements helps the user understand a proxy protocol with TCP configuration?

A) If the end user is requesting behind a proxy server then the user should not enable a proxy protocol on ELB
B) ELB does not support a proxy protocol when it is listening on both the load balancer and the back-end instances
C) Whether the end user is requesting from a proxy server or directly, it does not make a difference for the proxy protocol
D) If the end user is requesting behind the proxy, then the user should add the "isproxy" flag to the ELB Configuration