The information given about the teachers is limited to the fact they teach preschool.
B and D. If a teacher has more experience teaching, they are probably better at teaching. Even if the subject is not reading, they gain transferable teaching skills with experience.
C. Although both teachers teach preschool, one may have many more years of experience or other qualifications, which will likely help them to teach better in generally.
A. The samples 30 and 40 students in a typical class are enough to show different students' various learning styles and strengths. The sample size is big enough.
