Human Hearing Frequency Range Steps:

• Recall that human hearing detects sound waves as vibrations in the 20 Hz to 20 kHz range.
• Evaluate options against this standard: A matches exactly.
• Eliminate B and D for being too narrow or too broad.
• Dismiss C as it specifies the same frequency twice, implying no range.

Why A is correct:

• The audible range for a healthy human ear is defined as approximately 20 Hz (infrasonic bass) to 20 kHz (ultrasonic treble), per standard audiology.

Why the others are wrong:

• B: Too limited (200 Hz–2 kHz), excludes deep bass and high treble humans can hear.
• C: Invalid range (20 Hz to 20 Hz) with zero span, not possible for hearing.
• D: Upper limit (200 kHz) exceeds human capability, entering bat echolocation territory.

Final answer: A