题目选项分析

A shortage of orders for Manto Aircraft's airliners has led analysts to predict that the manufacturer will have to lay off workers. The new order that Consolidated Airlines has just made for 20 of Manto's model TX jets does not provide a reason for the analysts to revise their predictions ,because simultaneously with its new order , Consolidated canceled its existing order for an equal number of Manto's larger, more expensive model Z jets.

Which of the following ,if true, most seriously weakens the argument?

【选项】Manto includes all required maintenance work for the first five years in the price of each jet it sells .