According to the passage, murder occurs most frequently in the months of ______.

A．It is extremely dangerous to fly in the dark.
B．Noise regulations restrict the hours of airport operation.
C．Some of its runways are not in good condition.
D．Cargo planes produce more disturbing noises at night.

A．In an office.
B．In a restaurant.
C．In a department store.
D．In a factory.