Match the description of the murmur to the valvular lesion.

The defective valve impedes blood flow during ventricular systole. This results in a characteristic systolic murmur that increases in loudness to mid-systole and then fades gradually. The second heart sound may be softer than normal, too.

a. Aortic regurgitation
b. Aortic stenosis
c. Mitral regurgitation
d. Mitral stenosis