Which portion of the master production schedule is normally fixed, frozen, or firm?

A) the entire schedule
B) only the aggregate schedule
C) only the middle of the schedule
D) only the near-term portion
E) only the far-term portion

The near-term portion of the master production schedule (typically the first few weeks or months) is generally fixed, frozen, or firm, as it is closest to the current date and has already been planned and committed to production. The far-term portion may still be subject to change based on changes in demand, supply chain disruptions, or other unforeseen factors. Therefore, option D is the best choice.