The oxidation number of phosphorus in sodium hypophosphite is

Among the four oxidation states, it is asked for the oxidation number of phosphorus in sodium hypophosphite.

The chemical formula for sodium hypophosphite is NaPO₂H₂

Let the oxidation state of Phosphorus be x.

NaPO₂H₂ = +1(1)+x+(-2(2))+(2(+1))

=1+x-4+2

=3+x-4

x=+1

Hence, the correct option is C.