The In carbilamine test is used to detect the presence of primary amines. During this test, an amine reacts with chloroform and excess benzenesulfonyl chloride \((C_6H_5SO_2Cl)\) in the presence of a base like sodium hydroxide (NaOH). The resulting foul-smelling product is an isocyanide compound, \(CH_3NC\), which is given off as a gas.
Therefore, the correct answer is (A) \(CH_3NC\).