This question is incomplete, however, I will try to explain what a cover letter is about.
The options mentioned are the essential parts of a cover letter, nevertheless, there are some important issues that you have to bear in mind in each section:
A. Your contact information = It has to be clear, usually located at the top on the header of the document. Include everything: Complete name, email, phone number, do you have an online resume? if so, you can include the link here.
B. A salutation = It has to be polite and formal.
C. The body of the cover letter = It should contain the most important achievements, degrees and your experience in the field of work that you are applying to. Moreover, make sure to be polite but find your own style when describing this information.
D. An appropriate closing = A polite final greeting.
E. Signature = Another option here is to include below the signature your contact information.
