In the context of the meaning of work, which of the following statements is true?
a. Work means activities that involve perseverance, discipline, toil, usually performed with a degree of seriousness and concentration.
b. The meaning of work is likened with being idle, relaxing, playing, and activities such as reading a book or playing a round of golf.
c. Work does not include any task, accomplishment, or undertaking unless it generates an income.
d. An activity is not regarded as work unless the worker's identity and the activity are "morally inseparable."