The scientist presented a well documented report on the climate changes observed over the past decade.
Correct: A
When a compound adjective (like 'well-documented') modifies a noun (like 'report') and comes before the noun, it is typically hyphenated to show that the two words function as a single descriptive unit. 'Climate changes' does not form a compound adjective, so 'climate' and 'changes' should not be hyphenated. Option A correctly hyphenates 'well-documented' and leaves 'climate changes' unhyphenated.