\(K _{ a_1,}, K _{ a_2 }\) and \(K _{ a_3}\) are the respective ionization constants for the following reactions \((a), (b),\) and \((c)\). \((a)\) \(H _{2} C _{2} O _{4} \rightleftharpoons H ^{+}+ HC _{2} O _{4}^{-}\) \((b)\) \(HC _{2} O _{4}^{-} \rightleftharpoons H ^{+}+ HC _{2} O _{4}^{2-}\) \((c)\) \(H _{2} C _{2} O _{4} \rightleftharpoons 2 H ^{+}+ C _{2} O _{4}^{2-}\) The relationship between \(K_{a_{1}}, K_{ a _{2}}\) and \(K_{ a _{3}}\) is given as

1. A \(K_{ a _{3}}= K _{ a _{1}}+ K _{ a _{2}}\)
2. B \(K_{a_{a_{3}}}=K_{a_{1}}-K_{a_{2_{2}}}\)
3. C \(K _{ a _{1}}= K _{ z _{1}} / K _{ s _{2}}\)
4. D \(K _{ a _{3}}= K _{ a _{1}} \times K _{ s _{2}}\)