| Besides a visual inspection upon disassembly, what method can be used to check for suspected leakage through a heat transfer plate of a plate type heat exchanger? |
| A) One side of the plate is cleaned and coated with a water-seeking paste, and the other side is sprayed with water. |
| B) One side of the plate is cleaned and sprayed with a fluorescent dye penetrant, and the other side is viewed with an infra-red heat source. |
| C) One side of the plate is cleaned and sprayed with a fluorescent dye penetrant, and the other side is viewed with an ultra-violet light. |
| D) One side of the plate is cleaned and sprayed with a fluorescent dye penetrant, and the other side is viewed with an ordinary flashlight. |
