The type of tone a writer should use is respectful.
Explanation:
A job cover letter is the first view a company has of you as an applicant, then you have to make it as a representation of the summary of your best qualities, since this will be determining if they would like to interview you or not, the other options show a kind of personality that is normally avoided by employers at the moment of hiring.
The answer is d, Mrs Reed walks in on Jane reacting to abuse from Master Reed but gets into trouble due to it being unladylike, especially in comparison to the context of the novel