A vcr manufacturer receives 70% of his parts from factory f¹ and the rest from factory f². Suppose that 3% of the output from f¹ are defective while only 2% of the output from f² are defective. What is the probability that a randomly chosen part is defective?
a) 0.7%
b) 1.4%
c) 2.1%
d) 2.8%