Written acceptance of an offer

The following question is from F4 Global December 2014 Specimen Paper. Which TWO of the following statements in relation to a written acceptance of an offer are true under the UN Convention on Contracts for the International Sale of Goods? (1) It may not normally be withdrawn once it is posted (2) It may not normally be withdrawn after the offer reaches the offeree (3) It may be withdrawn before the offer reaches the offeree (4) It may be withdrawn at the same time as the offer reaches the offeree A 1 and 4 B 2 and 3 C 2 and 4 D 3 and 4 The correct answer is D I think statement No 2 is also correct because I think statement No 3 & 4 means statement No 2. Please help me about this, Sir! I also think the question and statements are also confusing. The question state "the written acceptance of an offer" and the statements state " offer and offeree " . In my mind, it shoud be " the acceptance and offerer". Why?