Amos orally agrees to hire Elizabeth for an eight-month trial period. Elizabeth performs the job magnificently, and after several weeks Amos orally offers Elizabeth a six-month extension at a salary...

Amos orally agrees to hire Elizabeth for an eight-month trial period. Elizabeth performs the job magnificently, and after several weeks Amos orally offers Elizabeth a six-month extension at a salary increase of 20 percent. Elizabeth accepts the offer. At the end of the eight-month trial period, Amos discharges Elizabeth, who brings suit against Amos for breach of contract. Is Amos liable? Why or why not?