The weather criterion to clear an aircraft for a visual approach is _____.

Clearing an aircraft for a visual approach requires that the weather conditions are suitable for visual flight rules (VFR) operations. This means that the visibility must be adequate, allowing the pilot to navigate and land visually without reliance on instruments. In VFR conditions, pilots can see and avoid obstacles and other air traffic, which is essential for safely executing a visual approach.

Other options describe conditions that do not meet the requirements for a visual approach. IFR conditions are generally characterized by low visibility and cloud cover, which would require the use of instruments for navigation and landing, while special VFR conditions may apply in marginal visibility scenarios but still necessitate specific criteria to be safely executed. A ceiling of at least 5,000 feet and visibility of at least 5 miles provides a good standard but represents more specific regulatory criteria rather than the broader requirement of being in VFR conditions. Thus, for visual approaches, clear visibility and ability to navigate visually are paramount, making VFR conditions the appropriate criterion.