Answer: I would contend that the right answer is actually the D) dangling construction.
Explanation: Just to elaborate a little on the answer, it can be added that this sentence is an example of a dangling construction because a dangling modifier, placed at the beginning of the sentence (as it is often the case) and next to the boy and not to Mrs. Jones, which is where it belongs, has led to suggest that the boy was once an old woman. It can be corrected, for instance, by placing the modifier next to Mrs. Jones and make her the subject of the sentence: "When an old woman, Mrs. Jones was visited by the boy in the nursing home." Likewise, the dangling modifier can be turned into a subordinate clause: "When she was an old woman, the boy visited Mrs. Jones in the nursing home."
