When new technologies make cleaner production possible,

a) emissions would fall under a system of fees, but would not fall under a system of transferable emissions permits unless the government bought back some of the permits.

b) Emissions would fall under a system of permits, but would not fall under a system of fees unless the government raised them.

c) the price of transferable permits would rise.

d) the quantity of transferable permits would rise

e) the quantity of transferable permits would fall