A factory has two machines. Machine A produces 40% of the total items, and 3% of the items produced by A are defective. Machine B produces the remaining 60% of the items. Let x be the proportion of items produced by B that are defective. For the events D: “item is defective” and B: “item is produced by machine B” to be independent, find x.
a) 0.012
b) 0.06
c) 0.03
d) 0.02