1. What does it take for a time travel story to be coherent?

1. What does it take for a time travel story to be coherent?

(A) That what it describes be physically possible, involve no miracles and no gratuitous conceptual change. (B) That what it describes be logically possible and involve no miracles. (C) That what it describes be physically possible and not involve gratuitous conceptual change. (D) That what it describes be logically possible, involve no miracles and no gratuitous conceptual change.