In order to prepare a `1^(@)`- amine incorporating an additional `CH_(2)` group from an alkyl halide, What reagent is often used as the nitrogen soure?

In order to prepare a 1^(@) amine from an alkyl halide with simultaneous addition of one CH_(2) group in the carbon chain, the reagent used as source of nitrogen is…..

In order to prepare a 1^(@) amine from an alkyl halide with simultaneous addition of one CH_(2) group in the carbon chain, the reagent used as source of nitrogen is…..

In order to prepare a 1^(@) amine from an alkyl halide with simultaneous addition of one CH_(2) group in the carbon chain, the reagent used as source of nitrogen is…..

In order to prepare a 1_(@) amine from an alkyl halide with simultaneous addition of one CH_(2) group in the carbon chain, the reagent used as source of nitrogen is:

In order to prepare a 1^@ amine from an alkyl halide with simultaneous addition of one CH, group in the carbon chain, the reagent used as source of nitrogen is ________.