What Did Barber and Colleagues Find When They Asked Students

What did Barber and colleagues find when they asked students to complete a daily sleep log and online diaries of perceived stress in life over a five-day period?

A) A few days of sleep deficiency early on in the week can add to psychological strain but can be offset with sleep later in the week.
B) Consistent sleep patterns can wear us down as the body then cannot adjust suitably to any inconsistency in sleep that may arise.
C) A few days of sleep deficiency early in the week can contribute to psychological strain later in the week despite attempts to offset with subsequent sleep.
D) A few days of sleep deficiency early in the week does not contribute to psychological strain.