<prompt> The ratio of the incidence of the disease among exposed and the incidence among non-exposed is calledOdds ratioRelative riskAttributable riskNone of the above  <response>: Relative risk RR or risk ratio is defined as the ratio between the incidence of disease among exposed persons and incidence among the non exposed.Incidence among exposedIQ --- x 100Incidence among non-exposedThe case-control study cannot give relative risk but from the case-control study, we can derive odds ratio. 