This question has more than one correct answer and all must be selected.

Select all the statements that are true.

Question $3$ options:

Failures are tolerable as long as their results are not catastrophic.

Infant mortality refers to the high failure rate often encountered in the very early stages of the lifetime of a product.

Recording the maintenance history of processes, machines, or equipment is important for preventive maintenance, but largely irrelevant for breakdown maintenance.

The MTBF distributions of products, machines, or processes that have "settled in$,"$ or gone beyond the infant mortality phase, often follow the normal distribution.

When identifying the optimal maintenance policy, the cost of inventory maintained to compensate for the downtime is a cost often ignored.