How Should a Nurse Distinguish a Grade 5 Heart Murmur

How should a 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, while 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, while a grade 6 heart murmur is heard when a stethoscope is off the chest wall.
C) A grade 5 heart murmur is moderately loud, while a grade 6 heart murmur is loud and has a palpable thrill.
D) A grade 5 heart murmur is faint, while a grade 6 heart murmur is moderately loud.