Final answer:
The preferred font style and size for official correspondence in business is Times New Roman, 12pt.
Step-by-step explanation:
The preferred font style and size for official correspondence in business is Times New Roman, 12pt. In block formatting, everything should be left-justified, single spaced, and double spaced between paragraphs. It is important to choose a font with good readability, and Times New Roman is a commonly used font in business communication.