Final answer:
The Pocket dosimeter provides an immediate reading, whereas film badges and other crystal-based monitors like those containing lithium fluoride chips require processing to reveal radiation exposure.
Step-by-step explanation:
The personnel radiation monitor that provides an immediate reading is the D. Pocket dosimeter. Unlike film badges or devices using lithium fluoride chips, pocket dosimeters are designed to offer an instant measure of radiation dose. The detection is based on the discharge of a rechargeable internal capacitor, and the cumulative amount of radiation exposure is indicated immediately by the scale that can be read through an eyepiece on the device.
Film badges, on the other hand, need to be developed like photographic film before showing the level of radiation exposure. Crystal-based monitors such as those using lithium fluoride chips or TLDs (thermoluminescent dosimeters) must also be processed to determine the dose of radiation absorbed over time.