Correct option is A
Pipes in series combination:
Pipes are said to be in series if they are connected end-to-end (in continuity with each other) so that the fluid flows in a continuous line without branching.
Discharge in each pipe is constant.
Head loss in each pipe is different.
Pipes in parallel combination:
The main pipeline divides into two or more parallel pipes and then reunites (or join) into a single pipe downstream.
The head loss in each pipe is the same.