Which reply from the relatives seems most intriguing and why?

The letter from the relatives in Sussex is most intriguing. Flora's Aunt Judith Starkadder (who is actually Flora's cousin but is how she signs her letter) refers to a "great wrong" done to Flora's father by her husband. There is also a reference that Flora has "rights" to which she is entitled. Since Flora knows nothing of a wrong done her father, she finds it a mystery just waiting to be solved.