Which of These Statements Correctly Summarizes the Research on What

Which of these statements correctly summarizes the research on what influences sexual orientation?

A) There is stronger research evidence for biological influences on sexual orientation than there is for environmental influences.
B) There is stronger research evidence for environmental influences on sexual orientation than there is for biological influences.
C) The evidence is equally strong for both biological and environmental influences on sexual orientation.
D) Little or no evidence exists for either biological influences or environmental influences on sexual orientation.