Introduction:
A letter is a written form of communication that is used to convey information, thoughts, or messages between individuals or organizations. It follows a specific format that includes various components. In this response, we will explore the format of a letter and identify the component that is not part of it.

Components of a Letter:
1. Date: The date is an essential part of a letter as it indicates when the letter was written. It helps in maintaining a record and provides a reference for future communication.

2. Greeting: The greeting is the salutation or opening of the letter. It is used to address the recipient or reader of the letter. Common greetings include "Dear," "Hello," or "To whom it may concern," depending on the level of formality and the relationship between the sender and recipient.

3. Body: The body of the letter contains the main content and message. It is where the sender expresses their thoughts, provides information, asks questions, or conveys any other relevant details. The body is typically divided into paragraphs to organize the information effectively.

4. Closing: The closing is the ending of the letter. It is a polite way of concluding the communication and often includes a closing phrase such as "Sincerely," "Best regards," or "Yours faithfully." The sender's name is usually written below the closing.

5. Signature: The signature is the sender's handwritten or typed name. It provides authenticity to the letter and indicates that it has been authorized by the sender. The sender may also include their job title or position below the signature.

Identifying the Component:
Looking at the given options, "Paragraph" is mentioned as a part of the format of a letter. However, this is not accurate as a paragraph is not a separate component of a letter. Instead, it is a formatting technique used within the body of the letter to organize the content into coherent and logical sections. Therefore, option D is the correct answer as it does not fit within the format of a letter.

Conclusion:
In conclusion, the format of a letter includes the date, greeting, body, closing, and signature. While a paragraph is used within the body of the letter for organization and clarity, it is not a separate component of the letter format.