They had helped us a lot and we just tried to return their benevolence. ( Complex)

• ক We just tried to return their benevolence, for they helped us a lot.
• খ If they had helped us a lot, we just tried to return their benevolence.
• গ When they helped us a lot, we just tried to return their benevolence.
• ঘ Since they had helped us a lot, we just tried to return their benevolence. ✅ সঠিক উত্তর