1. Massachusetts Board of Registration of Real Estate Brokers and Salespersons, 254 Code of Massachusetts Regulations (CMR) 3.00: Professional Standards of Practice. Section 3.00(10)(b) requires a broker to "convey all formal written offers to his or her principal," which establishes the seller's position as the decision-maker with the authority to accept or reject said offers. The regulation imposes no duty on the seller to accept.
2. Cornell Law School, Legal Information Institute (LII), "Contract Law." The foundational elements of a contract are offer and acceptance. An offer gives the offeree (the seller) the power to bind the offeror by accepting, but it does not impose a duty on the offeree to do so. The offeree can reject the offer, which terminates it.
3. Ling, D. C., & Archer, W. R. (2018). Real Estate Principles: A Value Approach (6th ed.). McGraw-Hill Education. Chapter 12, "Contracts for Sale and Closing," clarifies that the seller of a property is not required to accept any offer, regardless of the price. The decision to accept, counter, or reject remains solely with the seller until a contract is mutually executed.