What is true regarding the uses of servlets

A) A servlet can handle multiple requests concurrently, and can synchronize requests. This allows servlets to support systems such as on-line conferencing.
B) Servlets can forward requests to other servers and servlets.
C) Servlets can be used to balance load among several servers that mirror the same content, and to partition a single logical service over several servers, according to task type or organizational boundaries.
D) All of the above.