In which compound is the oxidation state of nitrogen $+1$?

$LiCoO_2$ crystallizes in a rhombohedral structure. Consider a situation where $50\%$ lithium $(Li)$ is extracted from the lattice. To keep the crystal electrically neutral,the change in the average oxidation state of $Co$ is

Oxidation number of Nitrogen in $NH_4NO_3$ is

What is the oxidation state of $S$ in $H_2SO_3$?

What is the oxidation number of chlorine in $ClO_3^-$?

Match List $I$ with List $II$ and select the correct answer using the codes given below the lists:

List $I$ (Compound)	List $II$ (Oxidation state of $N$)
$(A)$ $NO_2$	$(1)$ $+5$
$(B)$ $HNO$	$(2)$ $-3$
$(C)$ $NH_3$	$(3)$ $+4$
$(D)$ $N_2O_5$	$(4)$ $+1$

Codes: $A \quad B \quad C \quad D$