Staying up late and sleeping in on weekends, then going to bed early on sunday is most likely to have an influence on the rhythm.

This is most likely to have an influence on the circadian rhythm.

Circadian rhythm basically refers to our body's internal 24 hour "clock" that regulates the cycle between sleepiness and alertness. Our circadian rhythm basically tells our body when to wake and go to sleep. Factors such as sunlight, temperature and dietary intake can influence our sleep quality and feelings of restfulness. 

Provide additional information.

The correct answer is a.f.c