Where are the bridgemarks measured from at P-5?

The correct location for measuring bridgemarks at P-5 is the south end. In construction and engineering, bridgemarks are reference points used for surveying and alignment purposes. They are critical for ensuring that structures, such as bridges or roads, are correctly positioned and constructed according to plans.

In the context of measuring from the south end, this often aligns with standard practices in the industry, where one end of a structure is designated as the starting point for measurements. By measuring from the south end at P-5, it establishes a consistent reference for all further measurements, which enhances accuracy in the construction process.

The choice of the other options as starting points for measurements may not be standard or could create inconsistencies in data collection and reporting, which is why they do not serve as the correct points of reference in this instance.