What is the correct order of the parts in a formal letter?

• ক Salutation, Heading, Subject, Body, Subscription, Signature
• খ Heading, Body, Subject, Salutation, Subscription, Signature
• গ Heading, Body, Salutation, Subject, Subscription, Signature
• ঘ Heading, Salutation, Subject, Body, Subscription, Signature ✅ সঠিক উত্তর