An "E" tuning fork with a frequency of 329 Hz is used to test the "E" note of a piano. Four beats are heard. This means _____.
The piano key is in tune.
The piano key is out of tune and has a frequency of 333 Hz.
The piano key is out of tune and has a frequency of 325 Hz.
The piano key is out of tune and has a frequency of either 325 or 333 Hz
The piano key is in tune.
The piano key is out of tune and has a frequency of 333 Hz.
The piano key is out of tune and has a frequency of 325 Hz.
The piano key is out of tune and has a frequency of either 325 or 333 Hz