3. There are 100 computer science students at a school. Of these 28, 54, 23, and 15 CIS students are in Discrete Structures II, Fundamentals, Data Structures, and Foundations, respectively; 6 are in both Discrete Structures II and Data Structures; 18 are in both Discrete Structures II and Fundamentals; 2 are in both Fundamentals and Foundations; and 15 are in none of these courses. Additionally, no student may take Fundamentals and Data Structures, or Discrete Structures II and Foundations, concurrently a. How many CIS students are in both Data Structures and Foundations? b. How many CIS students are only enrolled in Fundamentals