Select the correct statement about elements of group 15th.

• A

  The order of stability of oxidation state for +3 is $\mathrm{B}{\mathrm{i}}^{3+}>\mathrm{S}{\mathrm{b}}^{3+}>\mathrm{A}{\mathrm{s}}^{3+}$ and for +5 is $\mathrm{B}{\mathrm{i}}^{5+}<\mathrm{S}{\mathrm{b}}^{5+}<\mathrm{A}{\mathrm{s}}^{5+}$
• B

  In the case of nitrogen, all oxidation states from +1 to +4 tend to disproportionate in acid solution.
• C

  There is considerable increase in covalent radius from N to P but from As to Bi only a small increase in covalent radius is observed.
• Correct answer
  D

  All of these

Hence, the correct answer is option: 'D'.