Which of the words below cannot be accepted in the following sentence?<br/><br/>As she sat <i>______</i> her desk, her thoughts drifted to the horrible accident in which she lost her only son.<br/><br/>Choose one answer.<br/><br/>a. at <br/><br/>b. by <br/><br/>c. behind <br/><br/>d. across <br/><br/>Is D the correct answer?