What condition must be met for SVFR approval concerning IFR aircraft?

For Special Visual Flight Rules (SVFR) approval concerning IFR aircraft, the critical condition is that IFR aircraft must not be in the vicinity. This condition is significant because SVFR is designed to allow pilots operating under visual flight rules to fly in conditions where visibility is below the minimums typically allowed for VFR operations, specifically in controlled airspace.

The primary purpose of this requirement is safety; if IFR flights are operating nearby, there could be potential conflicts or hazards due to differing flight rules and visibility conditions. By ensuring that IFR aircraft are not in the vicinity when SVFR is granted, air traffic control can maintain a clear separation between different types of operations and minimize the risk of mid-air collisions or other safety incidents.

Other choices focus on conditions that may not directly relate to or ensure the safety and separation needed for SVFR operations.