Final answer:
In standard block formatting for business letters, there should be a double space (four spaces) between the sender's address or letterhead and the date, which is option B. 4 spaces.
Step-by-step explanation:
The question is regarding the formatting of a business letter, specifically the number of spaces between the sender's address or letterhead and the date. According to standard block formatting conventions for business letters, after the sender's address, there should be a blank line followed by the date. Considering this formatting rule, the correct answer would be B. 4 spaces, which represents double spacing in a document that is single-spaced within paragraphs and double-spaced between them.