The correct answer is A) if you have a high confidence level, the chance of rejecting the null hypothesis is rare.
When a null hypothesis is being tested, the confidence level affects the testing process in that if you have a high confidence level, the chance of rejecting the null hypothesis is rare.
A null hypothesis in statistics is the kind of hypothesis that establishes that "no statistical significance exists is a set of a series of observations." It tries to demonstrtaes that there are no significant changes between the variables studied. The hypothesis is considered as a true hypothesis until another evidence supported by numbers and statistics nullifies it. Then an alternative hypothesis is considered. So yes, when a null hypothesis is being tested, the confidence level affects the testing process in that if you have a high confidence level, the chance of rejecting the null hypothesis is rare.