Final answer:
The Incline DB bench press is a variation of the DB Bench Press that changes the angle of the bench to emphasize the upper chest and anterior deltoids.
Step-by-step explanation:
The exercise that is a variation of the DB (D umbbell) Bench Press is D) Incline DB bench press. While the traditional flat bench press focuses on the pectoralis major, the incline bench press shifts some of the emphasis to the upper portion of the chest - the clavicular head of the pectoralis major - and the anterior deltoids.
Other variations listed, such as the Alt DB bench press and One arm DB bench, also modify the traditional bench press but change the movement pattern rather than the angle of the bench. The Decline DB bench press similarly alters the angle but targets the lower chest more. The incline variation, however, is notable for fostering upper chest development.