Which offer is irrevocable under common law?

Group of answer choices

Jan, a hairdresser, orally offers to sell her pet poodle to Ted for $200 & to keep the offer open for 30 days.

Jan, a hairdresser, orally offers to sell her pet poodle to Ted for $200 and to keep the offer open for thirty days if Ted will put $10 down & Ted does so.

Jan, a hairdresser, in writing offers to sell her pet poodle to Ted for $200 & to keep the offer open for 30 days.

none of the above are irrevocable.