1. If the number of machines is damaged every day and the cost of repairing machines and the probability of the occurrence of machine breakdowns based on the previous experience of the factory as follows:

number of damaged machines (units)	0	1	2	3	4
opportunity	0.05	0.30	0.40	0.15	0.10

The probability of the machine being damaged is at least 2 units.

a.0.40 b.0,75 c.0,65 d.others.