The average human being

The average human being can hear sounds of up to 20 kHz frequency; therefore, most of the sounds made by the tiny parts inside a computer — regardless of volume — are inaudible to the human ear, because their frequencies are often in the 100 kHz range — too high for the human ear to detect.

A.therefore, most of the sounds made by the tiny parts inside a computer — regardless of volume — are inaudible to the human ear, because their frequencies are often in the 100 kHz range — too high for the human ear to detect
B.therefore, because the frequency of the sounds made by the tiny parts inside a computer are often in the 100 kHz range, that makes them inaudible to the human ear
C.therefore, the frequencies of the tiny parts inside a computer—regardless of volume—often in the 100 kHz range, are inaudible to the human ear
D.most of the sounds made by the tiny parts inside a computer—regardless of volume—are therefore inaudible to a human being because of their frequencies being too high for the human ear to detect them
E.most of the sounds made by the tiny parts inside a computer—regardless of volume—are often in the 100 kHz range that is inaudible to the human ear

Is their is correctly used in OA

A