An item has an exponentially distributed time to failure.

Which of the following statements is wrong?

a) Although the failures are random, the tendency towards failure gets stronger as time increases

b) The only parameter of the exponential distribution is the hazard rate itself

c) The item does not have a memory, i.e. it does not "remember" for how long it has been in operation, as long as it is still working

d) Failures are completely random, so that preventive replacement is meaningless