A water system is replacing a $5,000-$ft section of $48-$in$.$ cast iron discharge pipe from a water treatment plant. The new pipe is to be $C900$ plastic. The design is for a similar head loss pattern and a $25-$MGD flow. If the Hazen$-$Williams head loss coefficient for the cast iron is $100$ while the C$900$ coefficient is $130,$ the minimum line size $($in$.)$ for the C$900$ replacement is most nearly:

A$.36$

B$.42$

C$.48$

D$.54$