Topic : ionization of acids and bases

Phosphoric acid ionizes in three steps with their ionization constant values $K_{a_1}$, $K_{a_2}$ and $K_{a_3}$, respectively, while K is the overall ionization constant. Which of the following statements are true? A. $\log K = \log K_{a_1} + \log K_{a_2} + \log K_{a_3}$ B. $H_3PO_4$ is stronger acid than $H_2PO_4^-$ and $HPO_4^{2-}$. C. $K_{a_1} > K_{a_2} > K_{a_3}$ D. $K_{a_1} = \frac{K_{a_3} + K_{a_2}}{2}$ Choose the correct answer from the options given below: