Answer: B. what a strenuous career it is that I've chosen!
Step-by-step explanation:
I was unable to access the passage in question but this should be correct.
The speaker in this instance is saying that the job they have is putting stress on them and they are bemoaning this fact.
More often than not, people in fulfilling jobs do not see it as stressful because stress happens when you don't really like the job you do so it gets you down. The speaker in question here is therefore most likely unfulfilled in their career and if this is the case for others around the same time then we can say that workers then did not find their jobs fulfilling.