Final answer:
The supplied reference information does not specify the number of days required for advance notification before a hearing by a Commission regarding broadcasting license regulations; therefore, an accurate answer cannot be provided without additional context.
Step-by-step explanation:
The question appears to pertain to regulatory requirements for license holders in the broadcasting industry, specifically regarding advance notification for hearings by a Commission. As provided in the reference information, maintaining a broadcasting license requires adherence to various regulations, including the equal-time rule for political candidates.
However, the specific number of days for advance notification before a hearing is not provided in the supplied reference, thus making it impossible to accurately answer the question without additional context or information about the governing laws or regulations of the Commission in question. It is standard practice for Commissions or regulatory bodies to define such notification periods in their rules and regulations.