I think a historian has to be curious to be successful. This is simply because if a historian does not have a drive to learn more information\, they will not try. However, if they keep the child-like mindset of always needing to know, they can go far with their discoveries and studies.
A: full of significance and purpose
The sentence is missing a subject.
D. "his sister, who had taken a sales job, learned shorthand and French in the evenings so that she might be able to get a better position later on"
