Aresearcher has sectioned a mouse embryo and has noticed that certain muscle components (especially myosin) aggregate around the early-stage cartilage of the ribs. which of the following is true of these presumptive muscles?

a. since they associate with the ribs, these muscles are likely developing intercostal muscles.
b. since they associate with the ribs, these muscles are likely developing intercostal muscles. as a result, these muscles (when fully developed) will to regulate the volume of the mouse's thoracic cavity.
c. these muscles (when they are fully developed) will to regulate the volume of the thoracic cavity.
d. since they associate with the ribs, these muscles are likely components of the diaphragm.
e. these muscles likely only serve a supportive role for the ribs and will play no role in breathing.