In Which Manner Does the Nurse Distinguish a Grade 5

In which manner does the nurse distinguish a grade 5 heart murmur from a grade 6 heart murmur?

A) A grade 5 heart murmur is heard with the diaphragm of a stethoscope, whereas a grade 6 heart murmur is heard with the bell of a stethoscope.
B) A grade 5 heart murmur may be heard when a stethoscope is partly off the chest wall, whereas a grade 6 heart murmur is heard when a stethoscope is completely off the chest wall.
C) A grade 5 heart murmur is moderately loud, whereas a grade 6 heart murmur is loud and has a palpable thrill.
D) A grade 5 heart murmur is faint, whereas a grade 6 heart murmur is moderately loud.