Question 4313
Audible warning signals must be used...
- of any sound.
- with a very high-pitched sound.
- with a sound that is not shrill.
Show answer and explanation
Correct answer: with a sound that is not shrill.
Audible signals must have a non-shrill sound, meaning one that is neither piercing nor unpleasant to hear. A very high-pitched sound is just the opposite, and you cannot use just any sound, such as a musical horn.