Human Auditory Frequency Range

Steps:

• Recall the standard human hearing range for normal adults is approximately 20 Hz to 20,000 Hz.
• Convert the upper limit to kilohertz: 20,000 Hz equals 20 kHz.
• Compare options to identify the pair matching 20 Hz low and 20 kHz high.
• Select the option using consistent and standard scientific notation.

Why C is correct:

• The audible frequency range for normal human hearing is defined as 20 Hz to 20 kHz, per standard audiology references.

Why the others are wrong:

• A: Both values are identical and far below the actual low-end threshold.
• B: Uses 20,000 Hz instead of the conventional 20 kHz notation for the upper limit.
• D: Reverses the limits, placing the high frequency as the low end.

Final answer: C