Explanation
A brownfield site is appropriate for development of LEED projects because it is a site that has been previously used for industrial or commercial purposes and may be contaminated by pollutants or hazardous substances.
Developing a brownfield site can help reduce environmental impacts, such as soil erosion, habitat loss, and water consumption, by reusing existing infrastructure and restoring degraded land. LEED projects can earn credits for developing on brownfield sites under the Sustainable Sites category. References: LEED v4 BD+C Reference Guide, Sustainable Sites, page 35; Best Management Practice #14: Alternative Water Sources1

The footprint of a building is the area of ground that it covers, defined by its perimeter. It's essentially the shape that results when you trace around the outer walls of a building plan. This term is used in architecture and urban planning to describe the space that a building occupies on a site. References: LEED Green Associate Candidate Handbook, U.S. Green Building Council resources

Harvesting rainwater reduces reliance on potable water for non-potable uses like irrigation and flushing.
LEED supports this approach under Water Efficiency credits for reducing potable water consumption.

The scorecard is the recommended tool for the project team to utilize in order to determine the target certification level. The scorecard is a document that lists all the prerequisites and credits available for a specific rating system, along with their point values and requirements. The project team can use the scorecard to track their progress and estimate their potential score based on their design strategies and performance goals. The scorecard also helps the project team to identify synergies and trade-offs among different credits, prioritize their efforts, and optimize their resources.
The other options are not useful for estimating the certification level, as they are tools for documenting or clarifying specific credits or issues. The credit submittal form is a template that guides the project team on how to submit the required documentation for each credit. The project CIR (Credit Interpretation Request) is a service that allows the project team to ask technical questions or request clarifications on credit requirements or standards from USGBC or GBCI reviewers. The certification level cannot be determined without complete drawings, as they are necessary to demonstrate compliance with credit criteria.
References: LEED v4 User Guide, p. 12 2; LEED v4 Reference Guide for Building Design and Construction, p. 21 1