In the lot of 100 items, two items are tested, and the lot is rejected if either of the tested items is found defective.

(a) Find the probability that a lot with k defective items is accepted.

(b) Suppose that when the production process malfunctions, 50 out of 100 items are defective. In order to identify when the process is malfunctioning, how many items should be tested so that the probability that one or more items are found defective is at least 99%?