Cuando el empleado del hotel es atento y cortés es bueno darle a. un ascensor b. una llave c. una propina d. un itinerario

C. una propina (i google translated because i know no Spanish at all) :))

Agame in which two or four players strike a ball with rackets over a net stretched across a court. the usual form (originally called  lawn tennis  ) is played with a felt-covered hollow rubber ball on a grass, clay, or artificial surface.