Which of these sentences from this passage has an error in hyphen usage?
a) I took Nancy into the living-room and made her lie down.
b) (You should know that my mother-in-law, Nancy, is eighty-nine years old.)
c) My mother-in-law asked me to come over to her house to help her with some manual labor.
d) Then I went to the kitchen and searched her medicine shelf for some fast-acting medication for her back pain.