Is definitely not C. because Dr. always has a period after it. Is not A neither. B and D. look similar. so is one of those 2 sorry. that's all i can help you with.
A cover letter is an accompanying letter that serves as
the introduction to your resume. No resume should be
sent without one. The cover letter is individualized for
each position for which you are applying. It is an
extension of your resume and reflects your knowledge
of the employer’s needs.
All the sentences in a paragraph should be unified and coherent.
Answer: sentences
From the topic sentence to the concluding sentence, they need to be unified and coherent for the writer to truly get their point across as it was intended.
Hope this helps! :)