Answer:
The correct answer is D. agreeableness
Step-by-step explanation:
There are five major personality traits, openness, extraversion, agreeableness, neuroticism, and conscientiousness. Extraversion starts declines from 30. Neuroticism also decreases with age but it slightly increases after 80.
Openness shows two relationships with age which is negative and linear. Agreeableness is one of the five personality traits and people with a high level of Agreeableness are usually warm, friendly. Agreeableness is the trait that shows a linear relationship with age. It comes at a peak between 50-70 years of age. Therefore the correct answer is D.