Scoliosis, a condition when the spine curves abnormally and throws the body out of line , can cause heart and lung problems as well as physical deformity

a) same
b) an abnormal curvature of the spine that throws the body out of line
c) a condition of the spine curcing abnormally and in which the body is thrown out of line
d) where the body is thrown out of line by an abnormal curvature of the spine
e) a condition of an abnormal curvature of the spine throwing the body out of line

The correct answer is B. But dont know why? Can anyone help?