Write exactly five words: begin with which, then use the technician as the subject, the simple past of rely, and the final preposition on. The procedure ___ has been revised.
Bonne réponse
which the technician relied on
Explication
The prescribed pattern begins with which and leaves on after the verb, producing a standard stranded-preposition clause. Placing on before which would also be grammatical in another task, but it would not satisfy the requested construction here.