$20-$ Project manager selection is usually made by the:

A$.$ Senior levels of management

B$.$ Customer$$s selection process

C$.$ Line management based upon cooperation on past projects

D$.$ Voting by the team members

$21-$ Changes in corporate strategy precede and lead to $\_\_\_\_\_.$

A$-$ Changes in the environment

B$-$ Better communication

C$-$ Increased productivity

D changes in an organization's structure