A class is divided into 4 groups. A bag contains pieces of paper that are red, blue, green, and yellow. For every blue- or green-colored piece of paper, there are 2 red- and 2 yellow-colored pieces of paper. The students are asked to pick a piece of paper to be put into a particular colored group. What is the probability that the first student will randomly pick a red-colored piece of paper or a blue-colored piece of paper? What additional information would be required to solve the problem? A. the dimensions of the bag B. the number of students in the class C. the sum of the number of green and yellow pieces of paper D. the number of students present in class on that day