Kjeldahl's method cannot be used to estimate nitrogen for which of the following compounds?

Among the compounds A and B with molecular formula C₉H₁₈O₃ , A is having higher boiling point the B. The possible structures of A and B are :

An unsaturated hydrocarbon X absorbs two hydrogen molecules on catalytic hydrogenation and also gives following reaction : B(3 - oxo - hexanedicarboxylic acid) X will be :-

For the following Assertion and Reason, the correct option is :

Assertion : The pH of water increases with increase in temperature.

Reason : The dissociation of water into H⁺ and OH^– is an exothermic reaction.