Which of the following carboxylic acids has lowest boiling point?

Identify the products of following reaction :

$$\mathrm{C}_6 \mathrm{H}_5 \mathrm{COOC}_2 \mathrm{H}_5 \xrightarrow[\text { dil. } \mathrm{H}_2 \mathrm{SO}_4]{\Delta}$$

Identify product '$$\mathrm{B}$$' in following reaction.

Cumene $$\xrightarrow[\Delta]{\mathrm{KMnO}_4, \mathrm{KOH}} \mathrm{A} \xrightarrow{\mathrm{H}_3 \mathrm{O}+} \mathrm{B}$$

Which of the following alkenes on oxidation by $$\mathrm{KMnO}_4$$ in dil. $$\mathrm{H}_2 \mathrm{SO}_4$$ forms adipic acid?