A combination of two or more pipes connected between two points so that the discharge divides at the first junction and re-joins at the next is known as ____________.

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.