According to product structure below with lead time measured in weeks, we can claim that the minimal planning horizon of master production schedule is A (LT=1) B (LT=3) C (LT=4) D (LT=1) D (LT=1) F (LT=5) D (LT=1) E (LT=2) E (LT=2) E (LT=2) 4 weeks 8 weeks 9 weeks 10 weeks