<span>D) Passing out the tests, the instructor smiled at me with understanding</span>
The correct option is D.
Although, the recipient address written at the back and the inside of a business letter usually carries the same basic information, but the address that is written at inside of the letter does not normally include the ZIP code; the ZIP code is written at the back of the letter alone.
The ZIP code refers to the specific number of digits that is written at the back of the envelope in order to make it easy to get the letter across to the recipient. <span />
