The answer is C. Appear is a verb and singular verbs normally end in -s. Also the sentence is talking about the conductor, not the pictures.
The answer is probably when. What are the options
I’ve read this book, assuming the time period, it was the spark of industry so many jobs had terrible conditions, the pay was low, people were exhausted from they’re jobs, and poverty was bad, the answer is
A.) they found their jobs boring and unfulfilling
