If the Minimum Efficient Scale in Aluminum Production Exceeds the Quantity

If the minimum efficient scale in aluminum production exceeds the quantity of aluminum any individual aluminum siding producer buys,

A) siding producers should integrate backward into aluminum production
B) there will be a monopoly in aluminum production
C) siding producers should not integrate backward into aluminum production
D) siding producers will be charged prices above what the cost of producing aluminum themselves would be
E) siding companies will switch to vinyl