Which of the following reactions of a diazonium salt involves the retention of the diazonium group?

Which of the following is the strongest base?

Identify the correct statements:
$(A)$ Primary amines do not give diazonium salts when treated with $NaNO_2$ in acidic conditions.
$(B)$ Aliphatic and aromatic primary amines on heating with $CHCl_3$ and ethanolic $KOH$ form carbylamines.
$(C)$ Secondary and tertiary amines also give the carbylamine test.
$(D)$ Benzenesulfonyl chloride is known as Hinsberg's reagent.
$(E)$ Tertiary amines react with benzenesulfonyl chloride very easily.
Choose the correct answer from the options given below:

Identify the major product formed from the following reaction sequence.

What is the major product formed when $C_6H_5CH_2NH_2$ reacts with nitrous acid $(HNO_2)$?

The product $C$ of the following reaction sequence is: