Statement : It has been reported in a recent study that intake of moderate quantity of milk chocolate reduces the risk of suffering from central nervous system related illnesses.Which of the following would weaken the finding of the study reported in the above statement?

In making decisions about important questions, you should be able to distinguish between strong arguments and weak arguments. Strong arguments are those which are both important and directly related to the question. Weak arguments are those which are of minor importance and also may not be directly related to the question or may be related to a trivial aspect of the question. Each question below is followed by two arguments numbered I and II. You have to decide which of the argument is a strong argument and which is a weak argument.