Rukmani feels especially saddened by Old Granny's death because she would have been able to help her.
Old Granny died of starvation and because Rukmani was busy trying to solve her own family's trouble, she was not able to help Old Granny. She even accepted Old Granny's last Rupee as a gift for her grandchild, not thinking that Old Granny needed the Rupee more to buy herself some food.
D.) Late Kingdom is the answer your looking for