单项选择题

For a 40wt%Sn – 60wt%Pb alloy at roomtemperature, Calculate the relative amount of each phase present in term of massfraction;

A.Wα=40%;Wβ=60%
B.Wα=60%;Wβ=40%
C.Wα=61.2%;Wβ=38.8%
D.Wα=38.8%;Wβ=61.2%