. . . . . . . an accident, the train will arrive in time.

The correct answer is D. Barring.

Barring means “except for” or “if nothing happens to prevent it.” In this case, the speaker is saying that the train will arrive on time, except for the possibility of an accident.

The other options do not make sense in this context. Besides means “in addition to” or “apart from.” Accepting means “agreeing to” or “receiving.” Despite means “in spite of” or “even though.”

Here are some examples of how the word “barring” can be used in a sentence:

• Barring any unforeseen circumstances, the meeting will start on time.
• The team is confident of winning the game, barring any injuries.
• The project is on track to be completed on time, barring any unexpected delays.