The three-compartment sink is the standard for manual warewashing in a professional kitchen. According to the FDA Food Code and ServSafe guidelines, the first sink is dedicated to washing. The water in this compartment must be at a minimum temperature of $110^{\circ}F$ ($43^{\circ}C$). This specific temperature is required because it is the threshold at which most commercial detergents become effective at breaking down food fats and greases. If the water is too cold, the detergent will not emulsify the grease, leaving a film on the dishes that prevents the sanitizer in the third sink from working effectively.

Managers must ensure that the sink is equipped with a thermometer to monitor the temperature throughout the cleaning process. If the water temperature drops below $110^{\circ}F$, it must be drained and refilled. The wash sink must also contain a detergent solution that is changed frequently to prevent the buildup of organic soil. For comparison, $171^{\circ}F$ (Option C) is the minimum temperature required for heat-based sanitizing in the third compartment if chemicals are not used, and $180^{\circ}F$ (Option D) is the required temperature for the final sanitizing rinse in a high-temperature commercial dishwasher. The $110^{\circ}F$ requirement for the first sink balances the need for chemical activation with the safety of the employee, as higher temperatures could cause burns during manual scrubbing. Maintaining this temperature is a critical "Active Managerial Control" point to ensure that the initial cleaning phase of warewashing is performed correctly, setting the stage for successful rinsing and sanitizing.