Answer:
Swimming is good exercise, so swimmers are more fit than runners.
Step-by-step explanation:
A non sequitur is a faulty logical connection between ideas.
Swimming may be a very good exercise, but that does not make swimmers more fit than runners. As we see, the conclusion (swimmers are more fit than runners) has nothing to do with the original statement (swimming is good exercise), and that is why this option is a non sequitur.