Consider the following statements:

I. Behavioral scientists find that perfection standards often discourage employees and result in low worker morale.

II$.$ Practical standards are also known as attainable standards.

III. Practical standards incorporate a certain amount of inefficiency such as that caused by an occasional machine breakdown.

Which of the above statements is $($are$)$ true?

Multiple Choice

I only.

II only.

III only.

II and III.

I, II$,$ and III.