The sky was so clear in fact that the communications crew and recovery team could watch the balloon ______ to its maximum altitude with the naked eye.

A．Corporate executives in general are worth the high pay they receive.
B．The income of corporate executives is proportional to the growth of corporate profits.
C．Corporate executives tend to take advantage of their position to enrich themselves.
D．The performance of corporate executives affects their own interests more than those of the shareholders.

A．doubtful
B．optimistic
C．positive
D．approving