The writer feels that the answer to the mystery, of humour given by the great minds of history is ______.

A．be prepared to fill in time by taking up housework
B．set up smaller private enterprises so that we in turn can employ others
C．create more factories in order to increase our productivity
D．be prepared to admit that being employed is not the only kind of work

A．economic freedom came within everyone's reach
B．patterns of work were fundamentally changed
C．to survive, everyone had to find a job
D．universal employment guaranteed prosperity