It is possible though not a sensible thing to do.
Dear Mr. President is a salutation of a business letter. The salutation goes at the beginning, thus that's how you got Dear.
The situation that requires the use of a colon is d) the salutation of a business letter. In formal business correspondence, it is customary to follow the salutation (e.g., "Dear Mr. Smith:") with a colon to denote the start of the letter's body. In contrast, personal letters typically use a comma after the salutation.
In a business letter =P
A salutation is an addressing to the person that the letter is addressed to and in a business letter you should always start with "Dear" and then add something like "Sir" or "Madam" immediately after it.
salutation
salutation
Before the body
A business letter's salutation should be followed by a colon. For example, "Dear Mr. Smith:" or "To Whom It May Concern:".
No, the date on a business letter should appear before the salutation. Typically, the format includes the sender's address, followed by the date, and then the recipient's address, leading to the salutation. This order helps maintain a clear and professional structure in business correspondence.
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D. All the above
Sometimes business letters include the salutation "to whom it may concern". It is better to say "Dear" and then the addressee's name, followed by a colon.