Mark the letter A, B, C, or D on your answer sheer to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.

Researchers have found that people are sleeping almost two fewer hours a night than they were in the 1960s, and our health is deteriorating as a result. 

A. improving 

B. degrading 

C. purifying 

D. elevating