Final answer:
Both Technician A and Technician B are correct as loose U-bolts and loose spring shackles could both be the cause of the truck's broken springs.
Step-by-step explanation:
Technician A and Technician B both propose possible causes for the truck's broken springs. Loose U-bolts and loose spring shackles can both contribute to the problem. Therefore, both Technician A and Technician B are correct (C) in this scenario.