Squid game meme/try not to laugh

Which sentence from a student's reflective essay contains a subject and verb error and needs to be edited? a. in my opinion, some of the voters seemed to need more information about their candidates. b. the documentary showed that dollars are often used instead of rubles in russia. c. the research shows that jackets made of wool are warmer than those made of cotton. d. in my opinion, either the doctors or the chief administrator need to make a quick decision.

Why is this passage an example of inductive reasoning? d: the author starts by using specific information in order to prove a more general theory

What is the main idea of this paragraph from the volcanoes section of the ready. gov website