Sorry Professor, you are correct, it should be 'factors' instead of 'integers'.
M8 - you said "'cause only in digit 2 can the difference of any two distinct positive factors be odd"
What about in the digit 6??
2 distinct positive factors are 2 and 3, and their difference is 1 as well??
From the question stem we are told that the difference of any two distinct positive factors
6 has four distinct posiitve factors 1,2,3 and 6. so the diff of any
factors of 6 won't be equal 1, except 3 and 2 of course.