Concept:
- A formal or official email follows a fixed structural order, just like a formal letter.
- The subject line always comes first since it appears before the email is even opened.
- Inside the email body itself, the order is greeting, then the main message, then the closing signature.
Step 1: Place the subject line.
The subject (A) is written first, in the subject field, before the recipient even opens the mail.
Step 2: Place the greeting.
Once the email is opened, it starts with a greeting or salutation (C), such as 'Dear Sir or Madam'.
Step 3: Place the body and signature.
After the greeting comes the main message or body (B), and the email ends with the sender's signature (D).
Step 4: Combine the full order.
This gives the sequence A, C, B, D, which matches only one option.
Final Answer: A, C, B, D