Real depression cannot be as easily overcome as

The conclusion shown from the Peter Principle
.............. 
A) is that in a hierarchy every employee who is
incompetent tends to rise to his level of
incompetence 
B) is that it is derived from the analysis of the
hundreds of cases of incompetence in organizations
which can be seen anywhere 
C) is assuring periodic requests for high performance 
D) is that having the employees do still better is
possible by never providing promotion for them 
E) is that in time every post tends to be occupied by
a person who's supposed to be incompetent to carry
out its requirements 
19. Doctors began treating malaria long before they
knew what caused it. The first recorded breakthrough
came in the 17th century when European
missionaries learned that the bark of South-
American cinchona trees contained the potent but
toxic remedy now known as quinine. By the time
pharmaceutical companies developed reliable
supplies, in the 1920s, a better treatment was
imminent. Chloroquine, introduced in 1943 by the
U.S. Military, was as potent as quinine -yet it was
longer active, cheaper to produce and so well-
tolerated that people no longer had to wait passively
for malaria to strike. They could take regular doses in
order to prevent the disease.
Before 1943, ..................... 
A) it was impossible for people to use a drug for the
treatment of malaria 
B) the existing drugs were not as safe as to use for
prevention of the disease as well as a cure 
C) there existed no pharmaceutical solutions to treat
the disease 
D) the drugs that were routinely used were reliable
but not active long enough 
E) quinine was the only safe drug to treat malaria
radically 
20. Doctors began treating malaria long before they
knew what caused it. The first recorded breakthrough
came in the 17th century when European
missionaries learned that the bark of South-
American cinchona trees contained the potent but
toxic remedy now known as quinine. By the time
pharmaceutical companies developed reliable
supplies, in the 1920s, a better treatment was
imminent. Chloroquine, introduced in 1943 by the
U.S. Military, was as potent as quinine -yet it was
longer active, cheaper to produce and so well-
tolerated that people no longer had to wait passively
for malaria to strike. They could take regular doses in
order to prevent the disease.