The following data cube represents a classification of number of students based on Test type, time and score level. Tesi Level 6 points a. List all possible cuboids. 4 points b. What is the total number of "Beginner" students in the "English" test if we need to materialize cells grouped by Level and Test. What type of OLAP operation was used? 4 points c. What is the total number of "Proficient" and "Expert" students in the "Math" and "Science tests during Q1 and Q2 (if we need to materialize set of cells grouped by Level, Time and Test). What type of OLAP operation was used