Which of the Following Statements About Gause's Studies of Competition

Which of the following statements about Gause's studies of competition between different species of Paramecium is false?

A) A species cultured by itself showed only the effects of intraspecific competition.
B) A species cultured with another species showed only the effects of interspecific competition.
C) Competitive exclusion did not always occur if the species' realized niches were sufficiently different.
D) His studies focused on the type of competition called exploitative competition.
E) His results showed that there was considerable niche overlap in the Paramecium species he studied.