Select the missing word in the sentence from the options given below:

I am writing with ____ to my application.

regard

The correct answer is Option (1) → regard

The word "regard" is a formal preposition that is used to express a relationship between two things. In this case, the relationship is between the person writing the letter and the person or organization receiving the letter.

The other options are not correct:

• Relate is used to show how two things are connected
• Account is used to describe the reason for something
• None of these is obviously incorrect.