Which of the Following Sentences Uses the Best Writing Style

Multiple Choice

Which of the following sentences uses the best writing style for a formal report?

A) After checking several references,the company decided to hire the consulting firm of Anderson,Williams,and Pardee.
B) After considerable research,we've decided to order the Aptura computer from ISB for our office staff.
C) I conducted extensive research that shows companies are recognizing the benefits of telecommuting.
D) My personal opinion is that we should implement the new tracking system at once.