What is a specific restriction on the placement of OGAFC?

The correct choice highlights a specific timeframe restriction on the placement of OGAFC (Open Grate Area Flow Control) structures, which must not occur between October 31 and April 1. This restriction is likely in place due to seasonal considerations, as adverse weather conditions during this period, such as freezing temperatures or snow, may interfere with proper installation, functionality, or maintenance of the OGAFC.

During this timeframe, ground conditions can change significantly, and any installation could be compromised by frost or other winter weather challenges. Ensuring that OGAFC remains effective and manageable throughout the season likely drives this limitation, as any issues arising from improper placement could lead to inefficient water drainage or increased maintenance requirements later on.

The other options describe restrictions that don’t align with the operational and environmental considerations relevant to OGAFC. The timeframe between March and October generally allows for optimal installation conditions, while placement restrictions after sunset and temperature limits do not consider the technical parameters governing OGAFC usage.