Final answer:
The correctoption is B) as each function is developed. The correct practice is to test a program as each function is developed, ensuring early error detection and iterative improvement throughout the development process.
Step-by-step explanation:
The best practice for testing a program is B) as each function is developed. This approach, often referred to as unit testing, ensures immediate feedback on code functionality and error detection early in the development process. Testing only at the end or when there appear to be problems can lead to difficulties in pinpointing where the bugs are, and it can be more time-consuming to fix.
Moreover, continuous testing aligns with the iterative nature of problem-solving and learning, where students engage with material actively and develop insight through practice and application. It is essential for students to understand that testing is not just a task to confirm that a program works, but it is an integral part of the development process to ensure quality, reliability, and alignment with design criteria and constraints.