'Confounding bias' in a case control study can be removed by:

Ans; C (Matching) Ref: Park 22nd editionExplanation:Confounder is a variable which is an independent risk factor for disease and is non- causal.ly associated with the exposure.That is the variable should be related to the disease and to the risk factor under study like shown in the following figure: To remove the effect of confounding at the design-stage, matching is done, i.e., cases and controls are similar with respect to confounding variable.