Which from following compounds does NOT contain phenolic - OH group?

Identify the major product formed when 2-Methylhexan-3-ol is heated with concentrated sulphuric acid.

Identify substrate ' $A$ ' in the following reaction.

$\mathrm{A}+\mathrm{CO}_2 \xrightarrow[6 \text { atm }]{398 \mathrm{~K}}$ Sodium salicylate $\xrightarrow{\mathrm{H}_3 \mathrm{O}^{+}}$Salicylic acid

Which among the following compounds has lowest boiling point?