Which of the following frequencies is commonly used in pure-tone audiometry?

In pure-tone audiometry, common frequencies used to assess hearing are typically within the range of human speech and understanding. The choice of 125 Hz is correct because it falls within the standard frequencies tested in audiometric evaluations. Audiologists typically test frequencies such as 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz, and so on, as these frequencies help to gauge a person's hearing sensitivity across the range most important for communication.

The other frequency options, such as 1500 Hz, while used in some tests, are not part of the standard set typically highlighted in pure-tone audiometry. Frequencies like 12000 Hz and 50000 Hz are well above the audible range for most individuals and are not tested in standard audiometric screenings since they do not align with the typical range of hearing assessment necessary for diagnosing hearing loss. Hence, 125 Hz stands out as a foundational frequency regularly utilized for measuring low frequencies in pure-tone audiometry.