(A): Isocyanides are prepared by carbylamine reaction.  
(R) : Carbylamine on reduction always gives `2^(0)` amines. 

Explanation

Carbylamine reaction : A primary amine, for example, n-butylamine forms foul smelling isocyanide or carbylamine when heated with chloroform and alcoholic potassium hydroxide.
` underset( " n - butylamine ")(CH_(3) CH_(2) CH_(2) CH_(2) NH_(2) + ) CHCl_(3) + 3 KOH overset (" Heat ") to underset(" n - butylisocyanide") (CH_(3) CH_(2) CH_(2) CH_(2) NC + 3 KCl + 3H_(2) O)`