Alnico, an alloy used extensively for permanent magnets contains iron, nickel, aluminium and cobalt in the following ratio _____________________?

Alnico, an alloy used extensively for permanent magnets contains iron, nickel, aluminium and cobalt in the following ratio _____________________?

A. 50 : 20 : 20 : 10
B. 40 : 30 : 20 : 10
C. 50 : 20 : 10 : 20
D. 30 : 20 : 30 : 20
E. 50 : 10 : 20 : 20