Final answer:
A ballast given a sound rating of "A" is not the loudest. The higher the decibel level, the louder the sound.
Step-by-step explanation:
A ballast given a sound rating of "A" is not the loudest. The sound rating scale is often referred to as the sound level or sound pressure level (SPL) and is measured in decibels (dB). The higher the decibel level, the louder the sound. Therefore, a ballast given a sound rating of "A" would actually be quieter than a ballast given a higher rating, such as "B" or "C".