Plug fuses of the Edison-base type shall be classified at not over 125 volts and ___________ and below.

The correct classification for plug fuses of the Edison-base type specifies that they must be rated for not more than 125 volts and a maximum amperage that aligns with typical usage scenarios. In this case, the correct maximum amperage is 30 amperes.

This rating is significant because plug fuses are designed to provide overcurrent protection in electrical circuits, ensuring safety by preventing too much current from passing through. If the amperage rating exceeds what the circuit can safely handle, it could lead to overheating, equipment damage, or even electrical fires.

Therefore, the specification of 30 amperes as the upper limit ensures that these fuses adequately protect standard residential and commercial circuits without risking safety. Other ampere ratings provided in previous answer options do not align with standard practices for Edison-base fuses, making 30 amperes the most appropriate choice for this question.