55. Which choice most effectively leads into the new subject of this paragraph while summarizing a main idea of the preceding paragraph?
Your Answer is
Correct Answer is A
Explanation
The topic asks to choose the content that can transition to this paragraph and summarize the content of the previous paragraph. The previous paragraph explained the ease of use of Morse code, and this paragraph explains that Morse code can guarantee people's safety when other equipment fails, so item A [because of its practicality] is correct.