Numerous studies have confirmed that a brisk walk 30 minutes each day is an adequate exercise for most healthy adults. Two of the most beneficial aspects are increased metabolism and joint flexibility. Equally important, however, are the mental benefits. A daily walk provides a chance to decompress from the stresses of the work day. A change of scenery and fresh air can brighten your mood. Which of the following sentences would be the best topic sentence for the paragraph?  

A. Giving the chicks medicated or non-medicated food is a controversial choice that you should make after speaking to your supplier of feed store personnel

B. Eggs should be collected daily from a mature hen to ensure the eggs are not fertilized

C. Set the hatching area temperature to 950F, reducing it by 50 each week after the chicks arrive.

D. Make sure the chicks have plenty of clean water in shallow containers, giving them sugar water on their first day for a boost of energy

A. Preposition

B. Adverb

C. Verb

D. Adjective

A. Therefore

B. Indeed

C. However

D. Especially