NUS has opened two classes, A and B, for GER1000, and each class has 100 students. In class A, every student scores 1 point higher in the final than in the midterm. In class B, every student scores 1 point lower in the final than in the midterm.

Which of the following statements is/are true?

a. The correlation coefficient between the final score and the midterm score in class A is 1.

b. The correlation coefficient between the final score and the midterm score in class B is -1.