A Newly-Premiered Play Just Ended That Evening at a Local

A newly-premiered play just ended that evening at a local theatre.Theatre management briefly interviews every eighth person leaving the theatre to see if that person will recommend the play at that theatre to other people.Identify the type of sampling used in this example.

A) Voluntary response sampling
B) Convenience sampling
C) Cluster sampling
D) Systematic sampling
E) Stratified sampling