The reaction produces a low yield of a primary amine because primary amines are electrophilic, causing them to undergo immediate alkylation and form secondary amines, which subsequently undergo alkylation to form tertiary amines.

The reaction produces a low yield of a primary amine because primary amines are unstable, causing them to revert to ammonia.

The reaction produces a low yield of a primary amine because primary amines are unstable, causing them to react with ammonia and form diamines.

The reaction produces a low yield of a primary amine because primary amines are nucleophilic, causing them to undergo immediate alkylation and form secondary amines, which subsequently undergo alkylation to form tertiary amines.