What best defines decision coverage?

Decision coverage is a testing metric that focuses specifically on ensuring that all decision points in the code have been evaluated during testing. This means that for every decision, such as an "if" statement or a conditional expression, both the true and false outcomes need to be tested at least once. This coverage is important because it helps identify any logical errors or untested paths in the code.

The essence of decision coverage is its ability to assess whether each decision in the code has been executed, thereby providing insight into the thoroughness of the testing process. Achieving complete decision coverage means that the software under test has been subjected to all possible decision outcomes, enhancing the robustness and reliability of the software.

The other options refer to different aspects of testing or metrics that do not accurately represent the focus of decision coverage. Options that relate to execution time or the number of decisions without specifically addressing the need for testing all paths of each decision are not aligned with the primary goal of decision coverage. Thus, the definition that emphasizes checking if all decisions have been made captures the true essence of what decision coverage aims to achieve in the context of software testing.