What is the major product of the nitration of benzoic acid?

The sodium salt of an $\alpha-$halogen carboxylic acid,when heated with sodium nitrite followed by hydrolysis,forms:

The compound which reacts with Fehling solution is

Which of the following compounds reacts with $NaHCO_3$ solution to produce a sodium salt and $CO_2$ gas: phenol,acetic acid,or $n$-hexanol?

The compounds that produce $CO_2$ with aqueous $NaHCO_3$ solution are:
$A$. Benzoic acid
$B$. Phenol
$C$. $2,4,6$-Trinitrophenol (Picric acid)
$D$. Cyclohexanecarboxylic acid
$E$. $4$-Methoxyphenol
Choose the correct answer from the options given below:

An optically active compound $'X'$ having molecular formula $C_4H_8O_3$ evolves $CO_2$ with $NaHCO_3$. $'X'$ on treatment with $LiAlH_4$ gives an achiral compound. Then $'X'$ is: