Remisers are....??

Hello, 

What are remisiers? Are they sub-brokers and members of stock-exchange.  Please help me out with the following CMA question :

Remisers are

a) Members of stock exchange

b) Speculators

c) Sub-brokrers

d) NOTA

There is confusion between a) and c). In scanner correct answer given is a) but text book defination given is "The sub-brokers employed by a member (sharebroker) to secure business are called remisers.

So, which one is correct??