Certification answer: Answer (d) is correct. The class is not an application because it lacks the main() method required to run a class in that manner.
Answer (c) is incorrect. If there was a main() method that created a ReadTemps object, the output would be 70. The call to put(int) in the class puts the three integers in the array at the first three positions of the buffer, replacing their original contents, and sets the position after them. The subsequent call to get() returns 70, the integer in the fourth position.
Answers (a) and (b) are incorrect.