Question: Randomised, controlled trials provide strong evidence that an observed effect is due to the intervention (the assigned exposure). One reason is because

A: when the participants are randomised, many characteristics and possible confounding factors are likely to be evenly distributed in the groups.
B: it is easier to measure the outcome variable with great precision in randomised, controlled trials compared to in other study designs.
C: the exposure level and the outcome are measured at the same time.
D: the study participants are volunteers and therefore motivated to take part in the study.
Please eliminate two incorrect options first, then think it step by step and choose the most proper one option.