(b) That's right. In this example, there is not sufficient agreement because the offer and the acceptance do not coincide. For the process of offer and acceptance to result in agreement, the terms of the offer must be accepted by the offeree without material changes. This is reasonable because the offer consists of the terms on which the offeror is ready to be bound. If an offeree indicates that they are willing to contract, but on different terms to those contained in an offer, this amounts to making a counter-offer which destroys the original offer.

In the past, unless exactly the same language was used in an offer and acceptance, the courts would construe an offeree's response as a counter-offer (the mirror approach). Nowadays, provided that the response does not materially differ from the language of the offer, it will be construed as acceptance rather than a counter-offer.

In this example, B's reply to A is a rejection, not an acceptance of A's offer. It is also perhaps a counter offer, since B seems ready to hire A at the going rate. Perhaps A will accept this offer.