4 . Hargren Publishing offers its Accounting textbooks as e- texts through its online homework management system . Purchase of an access code provides the student with access to the e- text and online learning materials for six months . During that time , students have access to updates to the text and learning materials . Hargren should recognize revenue for purchases of access codes :" A . at the end of the six - month access period . B. when they occur . C . over the six - month period during which the customer has access . D. at the beginning of the semester in which the student will use the access code