____ are types of changes that occur when text has been omitted from a document and must be inserted later.

A) Additions
B) Deletions
C) Modifications
D) All of the above

Omitted text means that something is missing and needs to be added later, so the correct type of change would be an addition. Deletions refer to removing existing text, and modifications involve making changes to existing text rather than inserting new text. Therefore, the only appropriate choice is A) Additions.