ï»¿ pH of weak acids

In the following multiple choice test, we often abbreviate $H_3O^+$ by $H^+$ (Which is actually false, indeed, $H^+$ is always fully hydrated in water!)

What is the hydrolysis equilibrium of citric acid ?

a) $H_3C_6H_5O_7$ $+$ $2H_2O$ $H_3O^+$ $+$ $H_5C_6H_5O_8^-$ b) $H_3C_6H_5O_7$ $+$ $H_2O$ $H_4C_6H_5O_7^+$ $+$ $OH^-$ c) $H_3C_6H_5O_7$ $+$ $H_2O$ $H_3O^+$ $+$ $H_3C_6H_4O_7^-$ d) $H_3C_6H_5O_7$ $+$ $H_2O$ $H_3O^+$ $+$ $H_2C_6H_5O_7^-$

For answers, use (possibly several times) the arrows ↑ Down! and ↓ Up! Complete please this question before moving on to the next one!

The correct answer is: d) $H_3C_6H_5O_7$ $+$ $H_2O$ $H_3O^+$ $+$ $H_2C_6H_5O_7^-$