Choice D is the best answer because it provides a detail about Elinor that is established in the text. The text indicates that although Elinor is “only nineteen,” she gives good advice and exhibits such a high level of understanding and judgment that she serves as “the counsellor of her mother.” Thus, Elinor is mature beyond her years.
Choice A is incorrect because it isn’t supported by the text: although the text says that Elinor advises her mother and often counteracts her mother’s impulses, there’s no mention of Elinor arguing with her mother or failing to change her mother’s mind. Choice B is incorrect because it isn’t supported by the text: although the text mentions that Elinor has strong feelings, it doesn’t indicate that she’s excessively sensitive when it comes to family issues. Choice C is incorrect because it isn’t supported by the text: there’s no mention of what Elinor thinks about her mother and no suggestion that she thinks her mother is a bad role model. Because she’s described as having “an excellent heart,” Elinor likely doesn’t think ill of her mother.