Returning a greeting to a disbeliever

If one of the People of the Scripture (i.e. Christians and Jews) greets you, saying: ¤ ¤ As-Salāmu `alaykum, ¤ ¤ then say (to him): ¤ ¤ Wa `alaykum. ¤ ¤ If one of the People of the Scripture (i.e. Christians and Jews) greets you saying: ¤ ¤ As-Salaamu `alaykum, ¤ ¤ then say (to him): ¤ ¤ And upon you .