What is the correct IUPAC name of the following compound?
5-cyano-N, 3-diethyl hexanamide
N-ethyl-3 -(2-cyanopropyl) pentanamide
N, 3 -diethyl-5-cyanohexanamide
3-(2-cyanopropyl)-N-ethyl pentanamide
Amide has higher priority than cyanide. Also, a group at nitrogen atom of amide is indicated by position 'N'.