On graded sites, the top of any exterior foundation shall extend above the elevation of:

The correct choice is that the top of any exterior foundation on graded sites should extend above the elevation of the street gutter at the point of discharge. This requirement is vital for proper drainage and to ensure that water flows away from the foundation, which is essential in preventing moisture problems and potential flooding in basements or crawl spaces.

When the foundation is set above the street gutter elevation, it provides a means to direct rainwater runoff away from the building. This is particularly important because the street gutter carries stormwater away from the roadway to drainage systems, and ensuring that the foundation is higher helps to mitigate the risk of water pooling near the foundation.

Being concerned about other options, while the elevation of the building entrance, lowest point of the lot, or driveway surface may be relevant in certain contexts, they do not specifically address the critical aspect of managing water drainage that the street gutter represents. The street gutter serves as a benchmark for ensuring that the foundation remains dry and safe from potential water intrusion.