In propane tanks, the Hydrostatic Pressure Relief Valve must be set at a minimum of:

The Hydrostatic Pressure Relief Valve in propane tanks is designed to protect the tank from overpressure conditions that can result from temperature changes and increased pressure due to thermal expansion. The minimum setting for this valve is critical to ensure the safety and integrity of the tank.

The correct answer of 375 PSIG is based on industry standards that dictate the minimum pressure at which this safety device must operate to effectively relieve excess pressure while still providing adequate safety margins. Setting it below this threshold could compromise the safety mechanism, potentially allowing overpressure situations to escalate to dangerous levels.

Moreover, the values indicated in the other options exceed this minimum requirement and are relevant for specific tank sizes or applications that may require stronger containment measures, but they do not represent the baseline standard for the Hydrostatic Pressure Relief Valve's minimum setting. Thus, the minimum setting of 375 PSIG ensures effective protection while adhering to safety regulations within propane handling and storage practices.