Which of the following statement is true regarding engagement workpapers?

a. Each workpaper should be signed and dated by the internal auditor performing the work.
b. Workpapers must be retained for five years.
c. Using prior workpapers can help the auditor avoid over-auditing.
d. Workpapers must be paper documents.
e. Copies of all documents examined should be included in the workpapers.

Ans: a. Each workpaper should be signed and dated by the internal auditor performing the work.