Consider the following statements about tests and test results: I. A test must be observable to be useful. II. A test may be material but not relevant. III. A test may be relevant but not economic....

Consider the following statements about tests and test results:

I. A test must be observable to be useful.

II. A test may be material but not relevant.

III. A test may be relevant but not economic.

Which of the above statements are true?

a. IT only

b. I and III only

c. II and III only