This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiotherapy, Subject name: Radiology
A deterministic effect 
Select and explain. 
A. Has a threshold in dose but the severity of the effect is otherwise dose-independent, B. Has a threshold in dose and the severity of the effect increases with dose, C. Has no threshold in dose and the severity of the effect is a constant function of dose, D. Has no threshold in dose and the severity of the effect increases with dose
B: Has a threshold in dose and the severity of the effect increases with dose
Answer: B: Has a threshold in dose and the severity of the effect increases with dose 
Explanation: Deterministic effect: severity increases with dose; practical threshold; the probability of occurrence increases with dose; e.g., cataract.Stochastic effect: severity independent of dose; probability of occurrence increases with dose; no threshold; e.g., cancerReference: Eric J Hall Textbook of Radiobiology for Radiologist; 5th edition