Which of the following processes can be used to oxidize toluene to benzoic acid?

Consider the following reactions. From these reactions,which reaction will give carboxylic acid as a major product?
$(A)$ $R-C \equiv N \xrightarrow[(i) H^{+}/H_2O]{\text{mild condition}} R-CONH_2$
$(B)$ $R-MgX \xrightarrow[(ii) H_3O^{+}]{\text{(i) } CO_2} R-COOH$
$(C)$ $R-C \equiv N \xrightarrow[(ii) H_3O^{+}]{\text{(i) } SnCl_2/HCl} R-CHO$
$(D)$ $R-CH_2-OH \xrightarrow{PCC} R-CHO$
$(E)$ $\text{Benzoyl chloride} \xrightarrow[(ii) Br_2/H_2O]{\text{(i) } H_2/Pd-BaSO_4} \text{Benzoic acid}$
Choose the correct answer from the options given below:

Identify the product $B$ in the following reaction.
Dry ice $\xrightarrow[\text{dry ether}]{CH_3MgBr} A$ $\xrightarrow{H_3O^{+}} B$

In the presence of air,the fermentation of ethyl alcohol by $Acetobacter$ $aceti$ bacteria forms:

The compound formed as a result of oxidation of ethyl benzene by $KMnO_4$ is

In the reaction,$x$,$y$ and $z$ are