In the popular block letter format, which of the following guidelines apply?

A) Use ragged, unjustified right margins.
B) Use fully justified margins on all sides and center the body of the letter on the page.
C) Start the sender's address, the dateline, and the complimentary close at the midpoint; align all other letter parts at the left margin.
D) Double-space all content to improve readability.

CIn the block letter format, all elements are aligned to the left margin, creating a "block" of text, which includes starting the sender's address, the dateline, and the complimentary close at the left margin, not the midpoint. This format typically uses ragged, unjustified right margins to maintain a clean and professional appearance. Fully justified margins and double-spacing all content are not standard practices for block letter formatting.