Final answer:
No, it is unlikely that a person could hear a sound of 40 dB at a frequency of 30 Hz.
Step-by-step explanation:
Sound is a wave that travels through the air or another medium, and its loudness or intensity is measured in decibels (dB). The human range of hearing typically falls between 0 dB (the threshold of hearing) and 120 dB (the threshold of pain). When it comes to frequency, the human range of hearing is generally between 20 Hz and 20,000 Hz.
A sound of 40 dB is generally considered to be in the range of quiet background noise or a whisper. However, a frequency of 30 Hz is at the lower end of the human range of hearing, and it may be difficult for most people to perceive such low-frequency sounds. Therefore, it is unlikely that a person could hear a sound of 40 dB at a frequency of 30 Hz.
Therefore, the answer to the question is No (B).