For the Reaction Below,which of the Following Would Take Place

For the reaction below,which of the following would take place once pure A and B are mixed together?
A + B
C

A) The concentration of C would increase for a time,then remain constant.
B) The concentration of A would increase for a time,then decrease.
C) The concentration of B would increase for a time,then remain constant.
D) More than one response is correct.