History: What is the commonly cited frequency range of human hearing?

What is the commonly cited frequency range of human hearing?

• 20 Hz - 15,000 Hz.
  While difficult to hear above 15,000 Hz usually, we commonly cite a larger range.
• 20 Hz - 20,000 Hz.
  Yes.
• 1.5 kHz - 5 kHz.
  This is the part of the range we are most sensitive to.