It is known that 2% of printers sold by suppliers' malfunction within one year. The suppliers offer a warranty period of one year.
(a) Find the probability that, out of twenty printers are selected randomly, exactly five printers malfunction within the warranty period.
(b) Determine the least number of printers, such that the probability that at least one printer malfunctions within the warranty period is more 0.9995.
(c) Using a suitable approximation, find the probability that, out of 1,000 printers, there are between 10 to 18 (inclusive) malfunction within the warranty period.