A patient suffering from cholera is given saline drip because

A. $$C{l^ - }$$ ions are important component of blood plasma

B. $$N{a^ + }$$ ions help to retain water in the body  

C. $$N{a^ + }$$ ions are important in transport of substances across membrane

D. $$C{l^ - }$$ ions help in the formation of $$HCl$$  in stomach for digestion