On May $1$ Ralph offers to cure and smoke Sam$$s pork, and promises to keep the offer open until June $1.$ On May $3$ Ralph mails Sam a letter revoking the offer. Sam receives and reads the letter on May $5$ and responds to Ralph on May $6.$ Ralph$$s revocation of the offer became effective on

Group of answer choices

May $3.$

May $5.$

May $6.$

no date because the offer is irrevocable.