Consider the following statements:

In the water-supply distribution network, the dead-end system is not favoured because:

a. it is cumbersome in terms of design.

b. the pressure at the dead-ends becomes undesirably low in the case of additional extensions.

c. it is difficult to maintain residual chlorine levels at the dead ends.

d. at the time of repairs, service connections beyond the point of repair are deprived of water.

Of these statements-