At times, a main idea may cover more than one paragraph. Which sentence best expresses the main idea of paragraphs 13 and 14?

A、It is important to schedule naps at midday instead of late afternoon, says Dr. Maas.;
B、People who take naps should be sure they are as comfortable as possible.;
C、Dr. Maas suggests simple steps people can take in order to have a good nap.;
D、For many reasons, says Dr. Maas, taking a nap is superior to taking a coffee break.