What Can We Conclude About the Relationship Between Attitudes and Proficiency

What can we conclude about the relationship between attitudes and proficiency in a second language?

A) After becoming proficient in French, English Canadians are no more positive about French Canadians.
B) A student's attitude toward a group that speaks another language is not related to his or her ability to learn that language.
C) People who are positive toward speakers of another language are likely to learn that language more quickly than those who are neutral or negative about that group.
D) Because attitudes are a topic from social psychology, and second-language proficiency is a topic from cognitive psychology, this kind of interdisciplinary research has not yet been conducted.