Which statement correctly describes placard placement and content requirements on a placarded straight truck?

49 CFR 172.504(a) (placarding required on each side and each end of the vehicle); 49 CFR 172.516(a) (each placard must be clearly visible from the direction it faces); AAMVA CDL Manual Sec. 9.3.10 (nhcdm.pdf p.9-7 — four-placard/front-rear-sides requireme

Getting placard placement wrong, even with the correct hazard class, is still a violation and still leaves responders unable to identify the hazard from certain approach angles, which is the entire safety purpose placards serve.