Bob has calculated PPK, PP, CP, and CPK; however, he has forgotten that his data are non-normal. Which of the following is true?

a) Non-normal data does not impact process capability indices.
b) Non-normal data may lead to underestimation of process capability.
c) Non-normal data always results in inflated process capability indices.
d) The impact of non-normal data on process capability indices is unpredictable.