The anwer is D) My primary quibble with ear buds is that they are very distracting devices and are therefore dangerous.
This is the sentence that would best serve as a topic sentence for this passage. In the passage, the author focuses on the fact that ear buds can be very distracting. He presents several examples of why this is the case. Moreover, he argues that ear buds can be dangerous, for example, when someone is driving. Option D discusses both of these facts, and therefore, fits the best with the paragraph.
Paragraph III is entirely concerned with how ear buds are distracting and therefore dangerous—thus My primary quibble with ear buds is that they are very distracting devices and are therefore dangerous is the best answer since it is most directly related to that topic
