Hal is the program manager for his organization. He would like your organization to provide his program with 4 tons of pea gravel for a construction project in his program. Hal send you a statement of

An invoice is a payment request submitted after goods or services are delivered - it is not a response to a procurement solicitation.

A Proposal is the response to a Request for Proposal (RFP), which is used when requirements are not fully defined and technical approach is evaluated alongside price.

An IFB is a procurement solicitation used when the buyer's requirements are completely specified and vendor selection is based primarily on price. The correct and expected vendor response to an IFB is a formal Bid, which is a price-based submission against fully defined specifications. Responding with a Bid is the standard procurement practice that matches the IFB solicitation type.

A Quote is the response to a Request for Quotation (RFQ), typically used for smaller, routine, or catalog-based purchases rather than formally solicited construction work.