The correct composition of Babbit metal is__________________?
A. 87.75% Sn, 4% Cu, 8% Sb, 0.25% Bi
B. 90% Sn, 2% Cu, 4% Sb, 2% Bi, 2% Mg
C. 87% Sn, 4% Cu, 8% Sb, 1% Al
D. 82% Sn, 4% Cu, 8% Sb, 3% Al, 3% Mg
E. none of the above