One day, the management staff of an elderly service center arranged activities for the elderly: In the morning, male seniors who were retired in the service center practised Tai Chi, and female elderly participated in choral exercises; after the lunch break, the physically weak elderly arranged indoor activities and had greater physical strength. Of seniors outdoors. which of the following can be inferred from this is:. ['Mother-in-law, Zhang, who was retired at the center, was indoors after lunch.', 'Male seniors not retired at the center practice Tai Chi in the morning.', 'Older male seniors at the center cannot be outdoors after the lunch break.', 'Some elderly people who are retired at the center may not participate in any activities.']