Question ID:PTJ2007 S3 Q17 Passage:When exercising the muscles in one's back, it is important, in order to maintain a healthy back, to exercise the muscles on opposite sides of the spine equally. After all, balanced muscle development is needed to maintain a healthy back, since the muscles on opposite sides of the spine must pull equally in opposing directions to keep the back in proper alignment and protect the spine. Stem:Which one of the following is an assumption required by the argument? Correct Answer Choice:BChoice A:Muscles on opposite sides of the spine that are equally well developed will be enough to keep the back in proper alignment. Choice B:Exercising the muscles on opposite sides of the spine unequally tends to lead to unbalanced muscle development. Choice C:Provided that one exercises the muscles on opposite sides of the spine equally, one will have a generally healthy back. Choice D:If the muscles on opposite sides of the spine are exercised unequally, one's back will be irreparably damaged. Choice E:One should exercise daily to ensure that the muscles on opposite sides of the spine keep the back in proper alignment.