1. Which of the following is a well-defined set? A set of beautiful sceneries b. A set of good basketball players A set of Philippine Presidents d. A set of successful leaders. C. 2. List all the letters in the word "school". {s, c, h, 0, 0, 1) b. {s, c, h, o, 1 ) a. c. {s, h, 0, 0, 1) d. {s, C, 0, 1) 3. Which of the following is the symbol of an empty set? a. n b. U C. d. 4. Which of the following is a subset of A= {1,2,3)? a. {0 b. {0,1} c. {1,2; d. 2,3,4 5. Given the set of letters in the word "mathematics", what is the cardinality of the given set? a. 11 b. 8 d. 4 c. 6​