Refer to the figure below.Which statement accurately describes the H zone and I bands of a sarcomere?

A) The H zone and I bands are regions of the sarcomere that appear light under the microscope because they both represent areas where myosin but not actin filaments are present.
B) The H zone and I bands are the only regions of the sarcomere that do not shorten or lengthen as the sarcomere contracts.
C) A shortening of the H zone is always accompanied by a shortening of the I bands,and a lengthening of the H zone is always accompanied by a lengthening of the I bands.
D) Stimulation by an action potential results in a lengthening of the H zone but a shortening of the I bands.
E) The H zone,but not the I bands,change in width during contraction of the sarcomere.