The correct option is C NH2CONH2
Percentage of N2 in following compounds is calculated by formula
(atomicweightofN2incompound/Atomicweightthecompound)×100
So, percentage of N2 in compounds is given as
In (NH4)2SO4 it is 21%
In Ca(NO3)2 it is 17%
In NH2CONH2 it is 47%
In NH4NO3 it is 35%.