Answer: The best cover letter for an unsolicited job is; "Because PublicOrg, Inc. is expanding its public relations department, are you in need of a candidate with ten years of public relations experience in the nonprofit sector? I would welcome the opportunity to enhance and strengthen your public relations department."
Step-by-step explanation:
In this cover letter, the potential employee is showing that they have 10 years experience in the field. This will stick out to the recruiters as they will see right off that this person has the needed experience for the same job they are hiring for. The potential employee shows that they have confidence by saying that they can "enhance and strengthen" the public relations department.
The cover letter should also include knowledge and interest of the business. Another thing that would be great to add for the cover letter is any special talents that they possess and all background information that can be an additional benefit for the company.