Read the text and answer question.
Significant review and repair bill await Spirit Airlines
In the FAA’s airworthiness directive, the FAA estimated only 20 engines on US-registered aircraft would be impacted, and it appears, according to the ch-aviation.com database, those impacted US-registered aircraft are in the Spirit Airlines fleet. According to the airworthiness directive, the FAA also estimated that the cost in time will be 100 work hours to conduct the ultrasound inspections and a financial cost of $170,000 per stage for a total financial cost of $340,000 per engine.
If the 1st-stage or 2nd-stage hubs need to be replaced, the cost per part will be an additional $171,000 for one hour. The FAA presumes all labor costs to be at the rate of $85 an hour.
Choose the alternative in which the pronoun “those” on the text refers best.
