Which of the following are three requirements for external fill connections on MWS apparatus?

The correct answer identifies three essential requirements for external fill connections on Mobile Water Supply (MWS) apparatus. A fill rate of 1,000 gallons per minute is critical for ensuring efficient refilling during operations, allowing for rapid turnaround times and minimizing downtime. The use of a strainer is essential to prevent debris and contaminants from entering the water supply, which could potentially compromise the water quality by clogging hoses or damaging the apparatus. Additionally, a slow-closing valve is necessary as it helps to avoid water hammer effects, which can cause damage to the plumbing and fittings due to sudden changes in water pressure.

These elements are foundational for maintaining both operational efficiency and equipment integrity when filling water tanks from external sources in emergency and non-emergency situations.