Cis-butene dioic acid $\overset{K_{a_1}(-H^+)}{\longleftrightarrow} X_1^- \overset{K_{a_2}(-H^+)}{\longleftrightarrow} X_2^{2-}$
Trans-butene dioic acid $\overset{K'_{a_1}(-H^+)}{\longleftrightarrow} Y_1^- \overset{K'_{a_2}(-H^+)}{\longleftrightarrow} Y_2^{2-}$
The incorrect statement regarding the above information is:

• A
  $X_2^{2-}$ species is more basic than $Y_2^{2-}$ species
• B
  $X_1^-$ species is more basic than $Y_1^-$ species
• C
  $K_{a_1}$ is greater than $K'_{a_1}$
• D
  $K'_{a_2}$ is greater than $K_{a_2}$