Of the following four items, which one is not necessarily required before you start writing your application letter?

A、Identify what skills you possess and analyze your strengths and weaknesses.;
B、Know something about the prospective company (its plans, products, policies and operations).;
C、Learn how your qualifications meet the company's goals, esp. the requirements of the work that the company wants.;
D、Try all means to brag about your accomplishments