In order to prepare a 1o amine from an alkyl halide with the simultaneous addition of one CH2 group in the carbon chain, the reagent used as a source of nitrogen is-

1.  Sodium amide, NaNH2

2.  Sodium azide, NaN3

3.  Potassium cyanide, KCN

4.  Potassium phthalimide, C6H4(CO)2NK+