What is the primary role of the vocal cords in speech production?

The primary role of the vocal cords in speech production is indeed to vibrate and produce voiced sounds while remaining apart for voiceless sounds. When the vocal cords come together and are brought into vibration by the airflow from the lungs, they produce voiced sounds, such as vowels and certain consonants like 'b' or 'z.' This vibration is essential for the characteristic qualities of many speech sounds.

Conversely, when the vocal cords are held apart, the airflow can pass through without causing vibration, resulting in voiceless sounds such as 'p' or 's.' This distinction in the function of the vocal cords is fundamental to how speech sounds are produced and categorized.

Filtering of sounds and aiding articulation are important, but they occur at different stages or through different mechanisms in the speech process. Thus, option B accurately captures the unique and vital function of the vocal cords in generating voiced sounds while allowing for voiceless production as well.