In a fencing match, if an infraction occurs and the Referee issues a warning, which card would likely be used?

In fencing, a warning is typically signified by the use of a yellow card. The yellow card serves as a formal notification to the fencer that they have committed an infraction but it does not carry a penalty beyond the warning itself. By issuing a yellow card, the referee is providing an opportunity for the fencer to correct their behavior without imposing a more severe penalty.

The green card indicates a caution but is more commonly used to signal lighter infractions or for positive actions, while the red card is associated with more serious penalties, such as disqualification. The blue card can also signify a warning but is not universally recognized in all forms of fencing. Therefore, the yellow card is the standard and widely accepted method for communicating a warning during a fencing match.