Which of the following methods can be used to prepare acetophenone?

$A$ man has been asked to synthesize the molecule shown in the image. He thought of preparing the molecule using an aldol condensation reaction. He found a few cyclic alkenes in his laboratory. He thought of performing an ozonolysis reaction on an alkene to produce a dicarbonyl compound,followed by an aldol reaction to prepare "$x$". Predict the suitable alkene that can lead to the formation of "$x$".

$C_6H_5CH_3$ $\xrightarrow{CrO_2Cl_2} A$ $\xrightarrow{H_2O} B$
The functional group present in $B$ and the name of the reaction are:

Which reagent is used in the preparation of benzaldehyde from benzene by the Gatterman-Koch reaction?

Identify the name reaction shown in the following chemical equation:

Identify the reagent '$A$' in the following reaction:
$C_6H_5COCl \xrightarrow{A} C_6H_5CHO$