You are carrying cargoes of crotonaldehyde，phosphoric acid，and morpholine on your multiple-product tanker. Which of the following statements is TRUE? （）
- AEach of the cargoes must be segregated from the other by at least two barriers
- BThe minimum protective clothing required for taking samples of phosphoric acid is goggles or a face shield
- CAluminum，copper，and zinc are prohibited in all valve parts in contact with these cargoes
- DThe required warning sign must have the legend "cancer hazard" added to it