You are testing a hypothesis; "students learn more if they drink tea before sitting for study". Your 20 experimental students drink tea before study; you test their learning by giving question. Your 20 students of the control group should have on experimental conditions identical to the experimental group EXCEPT that;

A ) They should take tea with more milk and sugar

B ) They should take tea before as well as during study

C ) They should not take tea before study ✅

D ) After taking tea, they should not sit for study