Which of the following reactions will produce $R-CO-Ar$?

The reaction shown below is known as:
$C_6H_6 + CO + HCl \xrightarrow{\text{anhyd. } AlCl_3} C_6H_5CHO$

The molecular formula of the final product of the following synthetic scheme is:

$CH_3-C(CH_3)(OH)-C(CH_3)(OH)-CH_3 \xrightarrow[H^{+}]{\Delta} ?$

Consider the following statements. Which of the following reactions can be used to prepare acetophenone?
$I.$ Oxidation of $1$-phenylethanol.
$II.$ Reaction of benzaldehyde with methyl magnesium bromide.
$III.$ Friedel-Crafts acylation of benzene with acetyl chloride.
$IV.$ Distillation of calcium benzoate.
Which of these statements are correct?

$Ph - C \equiv C - CH_3 \xrightarrow{Hg^{2+}/H^+} A$. What is $A$?