This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Screening, Subject name: Social & Preventive Medicine
Screening for condition recommended when- 
Select and explain. 
A. Low case fatality rate, B. Diagnostic tools not available, C. No effective treatment available, D. Early diagnosis can change disease course because of effective treatment
D: Early diagnosis can change disease course because of effective treatment
Answer: D: Early diagnosis can change disease course because of effective treatment 
Explanation: Ref:Parks 23rd edition pg 136. Screening is carried out in the hope that earlier diagnosis and subsequent treatment, orably alters the natural history of the disease in a significant propoion of those who are identified as "positive". Note: We don&;t do screening when the disease has a low case fatality ratio. Diagnostic tools/tests must be made available before doing a screening test. Otherwise it will be in vain. Effective treatment should be available prior to doing a screening test. Also Refer p. 135. Table 1.