Aperson who is typically deeply asleep is displaying which pattern of brain waves?
a. theta waves
b. beta waves
c. delta waves
d. alpha waves

 c.delta waves

During delta sleep, the person is already on the stage 3 and 4 of sleep. There are more than 50 percent of delta waves found during stage 4 of sleep. Hence, delta sleep or stage 4 of sleep is considered to be the deep sleep wherein it is difficult to wake sleepers.

When we're deeply asleep, we would usually witness delta waves - c. 

Delta waves are the type of brainwaves which are usually present during our deep sleep periods of our sleeping patterns. Shorter instance of other brainwaves might also occur but delta waves indeed are the ones which occur most often. 

True my friend : ) good luck