Which statement is true about effect modification? a) Effect modification is the error which occur during the process of designing a study b) Effect modification is the error which occur during the...

Which statement is true about effect modification? a) Effect modification is the error which occur during the process of designing a study b) Effect modification is the error which occur during the process of conducting a study c) Effect modification should be eliminated or minimized through study design and conduct   d)Effect modification is a biological phenomenon that you want to understand