单项选择题

A.3000(P/F,IRR,1)+12000(P/F,IRR,2)-10000=0
B.3000(P/F,IRR,2)+12000(P/F,IRR,1)-20000=0
C.3000(P/F,IRR,1)+12000(P/F,IRR,2)-20000=1
D.3000(P/F,IRR,2)+12000(P/F,IRR,1)-20000=1