The main purpose of the last paragraph of Passage 1 is to offer

“justification” is the best answer. The first two paragraphs of Passage 1 describe what might seem like extremely harsh restrictions on wireless transmissions: “no electronic transmitters at all,” “you’re not even allowed to cozy up to an electric blanket,” “a police officer roves the streets listening for forbidden wireless signals.” The last paragraph of Passage 1 serves mainly to offer justification: the restrictions are “necessary” because “the town is home to the Green Bank Telescope,” and “a rogue radio signal could prevent potential discoveries.” “criticism” is incorrect because the last paragraph of Passage 1 does not take a critical tone toward the electronics restrictions in Green Bank, instead describing them as “necessary.” 2 other choices are incorrect because no example is being given nor is a comparison being made; the whole passage is about Green Bank and its electronics restrictions.