correct answer is D top down , not C
Bottom up—Testing begins with atomic units, such as programs or modules, and works upward until a complete system testing has taken place. The advantages follow:
– There is no need for stubs or drivers.
– Testing can be started before all programs are complete.
– Errors in critical modules are found early.
• Top down—Testing follows the opposite path, either in depth-first or breadth-first search order. The advantages follow:
– Tests of major functions and processing are conducted early.
– internal application Interface errors can be detected sooner.
– Confidence in the system is increased because programmers and users actually see a working system.