Answer: A
Test the meaning and usage of verbs. The subject of the sentence is flightattendants (flight attendants), and the object after the space is duties (obligations, responsibilities), so it is obvious that the verb perform with the meaning of "perform, execute" should be selected. The remaining three items are inconsistent with the context: achieve means "to complete, reach", comprehend means "to understand", and proceed means "to proceed, to continue".