Choose the appropriate Passive Voice of the given sentence.

She is to write a letter.

A letter is to be written by her.

The correct answer is Option (2) - A letter is to be written by her.

• The original sentence "She is to write a letter" implies an expectation or scheduled task for her to write a letter.
• In converting to passive voice, the object "a letter" becomes the subject.
• The structure "is to write" converts into "is to be written" when changing from active to passive voice.
• Finally, "by her" indicates who is expected to perform the action.
• Therefore, the complete passive sentence is: "A letter is to be written by her."