What is the difference between a forward proxy and a reverse proxy in terms of which side they serve?

A A forward proxy sits in front of servers to balance load; a reverse proxy sits in front of clients to filter content B A forward proxy acts on behalf of clients (hiding them from servers, e.g. for filtering or anonymity); a reverse proxy acts on behalf of servers (hiding them from clients, e.g. for load balancing or SSL termination) C They are functionally identical; the names simply describe the direction of traffic flow through a firewall D A forward proxy only works with HTTPS traffic, while a reverse proxy only works with plain HTTP