Sally offers to sell Becky, a baker, 100 pounds of flour every month for $1/pound for twelve months. Becky readily agrees and notes that she will need 200 pounds in December to cover Christmas Cookie orders. Sally says nothing, but sends Becky 100 pounds of flour for the months September to December. Becky balks! She needs another 100 pounds of flour. Can Sally refuse? Why/not? Use contractual terms and concepts from the lecture. Make the best argument possible for both Sally and Becky.