An education researcher was interested in examining the effect of the teaching method and the teacher on students' reading levels. 257 students participated in an experiment. there were two different teachers (juliana and felix) and three different teaching methods (a, b, and c). students were randomly assigned to a teaching method and teacher. at the end of the semester the students took a reading test on which they received a score out of 20. students who studied with felix using method b achieved the highest scores. identify the factor(s) in the experiment and the number of levels for each. a) teaching method (3 levels) and teacher (2 levels) b) juliana and method a, juliana and method b, juliana and method c, felix and method a, felix and method b, felix and method c (6 levels) c) the teacher and teaching method combination (6 levels) d) teaching method (3 levels), teacher (2 levels), score on reading test (20 levels)