P Block Elements

Thionyl chloride on reaction with white phosphorus gives a compound of phosphorus ' $C$ ' which on hydrolysis gives an oxo acid ' $O$ '. The correct statement about $C$ and $O$ are

I. Shape of ' $C$ ' is pyramidal

II. ' $O$ ' is a dibasic acid

III. ' $O$ ' is a monobasic acid

IV. ' $C$ ' on reaction with acetic acid given ' $O$ '