B is the best approach to resolve the problem of not being able to decompose the system testing work package yet. The system development work package should be decomposed now, while the system testing work package can be decomposed later when more details about the 50% completed system are available, using an iterative planning technique called rolling wave planning. Rolling wave planning involves planning work to be done soon in detail while planning future work at a higher level, since all details may not be known far in advance.