D). The cause is if the illness was suspected, and the effect is immigrants were detained.
Explanation:
The cause-and-effect structure is primarily used to denote the reasoning for a specific problem or issue and the effects brought by the causes.
The last statement i.e. 'the cause ... detained' aptly relates that the given excerpt from 'Island of Hope' employs the 'cause-and-effect' structure and explains it. In the given paragraph, the organization of the cause 'if the illness is suspected' followed by the effect 'detaining of immigrants' assists the readers to identify the probable consequences associated with the action and understand the idea clearly. Thus,<u> option D</u> is the correct answer.
