R2d § 45
Option Contract Created by Part Performance or Tender
(1) Where an offer invites an offeree to accept by rendering a performance and does not invite a promissory acceptance, an option contract is created when the offeree tenders or begins the invited performance or tenders a beginning of it. (2) The offeror's duty of performance under any option contract so created is conditional on completion or tender of the invited performance in accordance with the terms of the offer.
Professor's notes
Elements: (1) where an offer invites acceptance by performance and does not invite a return promise, an option contract is created when the offeree tenders or begins the invited performance; (2) the offeror's duty of performance is conditional on completion or tender of the invited performance in accordance with the offer.
Yaros v. Trustees shows the protective function: once the offeree starts performance on a unilateral offer, the offeror cannot yank the offer mid-stride.
Common misunderstanding: students think § 45 binds both sides. It does not. The offeree may walk away; the offeror cannot revoke. It is a one-way option, created to solve the unfairness of Petterson v. Pattberg-style mid-performance revocations.
Cases that operationalize this rule
Text
R2d § 45. Option Contract Created by Part Performance or Tender.
(1) Where an offer invites an offeree to accept by rendering a performance and does not invite a promissory acceptance, an option contract is created when the offeree tenders or begins the invited performance or tenders a beginning of it.
(2) The offeror’s duty of performance under any option contract so created is conditional on completion or tender of the invited performance in accordance with the terms of the offer.