Checking that at least 50% of decisions have been exercised by a test case suite is not a valid use of decision coverage, because it does not meet the minimum criterion of decision coverage, which is to exercise all possible outcomes of each decision in the software under test . Decision coverage is a technique that measures how much of the logic or branching of the software under test has been exercised by the test cases . The other options are valid uses of decision coverage. Option A is a valid use of decision coverage, because it can check that all decisions have been exercised in a single program . Option B is a valid use of decision coverage, because it can check that all decisions have been exercised in a business process . Option C is a valid use of decision coverage, because it can check that all calls from one program module to another have been made correctly .