(A) The probability that you roll a 1 would be 1/6 because there are six sides of a dice and only one is a 1.
(B) The probability that you either roll a 1 or don't roll a 1 is 1/6 and 5/6, since the probability that you do roll a 1 is 1/6 and the probability that you don't is 5/6 since the other 5 sides of the dice are not ones.
(C) As stated above, the probability of not rolling a 1 is 5/6 since there are 6 sides of the dice and 5 are NOT ones.
Hope that helped!