article: Mrs. Baker's sister was ill. She had someone to look after her from Monday to Friday, but not at the weekend, so every Friday evening Mrs. Baker used to go off to spend the weekend with her at her home in a neighbouring town. But as Mr. Baker could not cook, she had arranged   for his sister to come over and spend the weekend looking after him at their home. This meant that Mr. Baker had busy time when he came home from work on Friday evenings. First he had to drive home from the railway station. Then he had to drive his wife to the station to catch her train. And then he had to wait until his sister's train arrived, so as to take her to his house.
  Of course, on Sunday evening he had to drive his sister to the station to catch her train back home, and then wait for his wife's train, so as to bring her home.
  One Sunday evening, he had seen his sister off on her train and was waiting for his wife's arrival when a porter (  ), who had often seen him at the station, came over and spoke to him, "You are having a lot of fun," he said, " But one day one of those women is going to catch you with the other, and then you will be in real trouble!"
question: Who looked after the sick person on weekdays?
options: Mr. Baker's sister Mrs. Baker's sister Mrs. Baker Someone acting as a nurse