Why have the avenues of exchange they provided been open only for limited time spans & then blocked for years or decades at a time?

Ashort story about human cruelty is adapted for dramatic radio broadcast. what choice might the broadcast's producer make to present the theme effectively? a. play suspenseful music when a character is acting cruelly o b. have an actor step out of character to deliver a moral to the audience o c. insult the audience throughout the broadcast o d. have the actors share memories of times when they were cruel