A backup of all files that are new or modified since the last full backup is

A.
In incremental backup

B.
A father/son backup

C.
A differential backup

D.
A full backup

Explanation:
“Incremental backup -A procedure that backs up only those files that have been modified since the
previous backup of any sort. It does remove the archive attribute. Differential backup – A procedure
that backs up all files that have been modified since the last full backup. It does not remove the
archive attribute.” – Shon Harris All-in-one CISSP Certification Guide pg 618