The correct option is A Methylcyanide
Cyanide ion (CN−) is the ambident nucleophile and can form different product with same substrate.
CH3−Cl+KCN→CH3CN+ CH3+N≡C−+KCl Methylcyanide Methylisocyanide Major Minor
Here, KCN is predominantly ionic and exist as free ions in solution. C site is more nucleophilic than N site and available to attack the methyl chloride. Hence, the major product will be methyl cyanide