The preliminary certification stage requires specific documentation to verify the implementation of efficiency measures like Insulation for Cold Storage Envelope. The EDGE Certification Protocol outlines the evidence requirements: "For measures involving insulation, such as Insulation for Cold Storage Envelope, the Client must provide drawings at the preliminary certification stage that specify the U-value of the installed insulation to demonstrate compliance with the measure’s requirements. The U-value must be lower than the Base Case to qualify for savings" (EDGE Certification Protocol, Section 3.2: Audit Requirements). Option C, drawings showing the U-value specification of the cold storage envelope, directly aligns with this requirement. Option A (calculations of Coefficient of Performance) is irrelevant, as COP applies to HVAC systems, not insulation: "COP is used for chillers, not insulation measures" (EDGE User Guide, Section 4.2: Energy Efficiency Measures). Option B (manufacturer's data sheets for the HVAC system) is also unrelated, as the measure focuses on the envelope, not HVAC: "HVAC documentation is not required for insulation measures" (EDGE Certification Protocol, Section 3.2: Audit Requirements). Option D (purchase receipts showing the U-value) is more relevant at the post-construction stage: "Purchase receipts are typically required at the post-construction stage to confirm installation, while drawings suffice for design-stage verification" (EDGE Certification Protocol, Section 3.4: Post-Construction Requirements). Thus, drawings with U-value specifications (Option C) are required at preliminary certification.