Topic: Sentence (বাক্য),

Best Answer Explained in Below-:

The question "He is going to take a train" provides information about a person's intended action. The correct option, "B) What's he going to take?", is the most appropriate response because it directly asks for clarification regarding the specific item or method involved in his action. This question seeks to gain insight into what he is planning to use, thus maintaining the focus on the object (the train) of his forthcoming journey.

Option A, "What was he going to do?", shifts the timeframe to the past and asks about an action he intended rather than what he is currently planning, which makes it less relevant. Option C, "Is he going to take a train?", reformulates the statement into a yes-or-no question but does not seek to gain further information about the specific aspect of the action. Similarly, option D, "He is going to take a train, isn't he?", although providing affirmation, does not seek any additional details about the action. Therefore, option B stands out as the best choice since it appropriately probes for specific information and aligns with the nature of the original statement.