A) The old geezer aggravated his younger counterparts by consistently producing more work than them.

B) The old geezer aggravated the younger counterparts by consistently producing more work than they.

C) The old geezer irritated the younger workers by consistently producing more work than them.

D) The old man irritated his younger workers by consistently producing more work than them.

E) The old man irritated his younger workers by consistently producing more work than they.

Explanation:
(E) Geezer and counterparts are jargon and should be avoided.
A wound or sore is aggravated; a person is irritated.
They is subject of the understood produce, not the object. Hence (E) is correct.
The old man irritated his younger workers by consistently producing more work than they did (better than Them did)