Which statement is true regarding myocardial functioning in the normal heart, based upon the Frank Starling law?

An increase in afterload results in decreased systolic pressure, which creates a decreased cardiac output.

A decrease in afterload causes the cardiac muscles to hypertrophy, resulting in increased diastolic volume.

An increase in preload results in greater shortening of myocardial fibers, thereby increasing contractility.

A decrease in preload results in increasing diastolic muscle fiber length, which impedes contractility.