Ans: C. Receiver-operating characteristic curve(Ref http:ilvvwwlexjansen.com/nesteg/ne.sug10/hl/h107.pdf)Receiver-operating characteristic (ROC) curve:Defined as a plot of test sensitivity as they coordinate versus its I-specificity or false positive rate (FPR) as the x coordinate.Graphic presentation of relationship between both sensitivity & specificity.Uses:Effective method for evaluating diagnostic test's performances.Excellent way to compare diagnostic tests.Best for determining threshold for diagnosis of positive test.Helps decide optimal model through determining best threshold for diagnostic test.