Answer: b) one tailed test.
Step-by-step explanation:
To prove that the new method of teaching economics is better than the traditional one we have make reference to mean score of students (for example) in their past exams.
Let us assume that from past exams, the mean score of students in economics exams has a value of 40.
After trying the new method in teaching, the students did economics exam and have an average of 65, this is obviously and improvement that can only be validated by performing an hypothesis test on the sample mean score.
Because the teacher is trying to prove that her method is better than the traditional, she will have to perform a one tailed test to prove that the mean score of her teaching method (65) is greater than the mean score of the traditional (40).
Due to the fact that she is opting to prove a point in just a single direction ( that her methods brings larger score compared to the traditional) a one tailed test is the perfect option.