When you edit a document that has the track changes feature enabled, word marks all text or graphics that you insert, delete, or modify and refers to the revisions as

 Markups

Explanation:

Markup is the feature that is present in Word that helps in tracing the changes that are made in a document and showing it through markings .Markups are shown through different color and lines according to the alteration made in document.

It can display insertions, deletions,formatting etc of text through selecting the related option.No markup option is present for hiding the marks as well.

the correct answer is a