A Researcher Measures the Amount of Time Older Adults Spend

A researcher measures the amount of time older adults spend each week engaging in mentally challenging activities and also obtains the scores they earn on a psychometric test of intelligence.The researcher finds that the more time older adults spend engaging in mentally challenging activities,the higher their scores on the psychometric test.On the basis of this finding,which of the following conclusions would the researcher be most justified in drawing?

A) Engaging in mentally challenging activities causes psychometric test scores to increase.
B) Spending too little time engaging in mentally challenging activities causes psychometric test scores to decline.
C) Amount of time spent engaging in mentally challenging activities and scores on a psychometric intelligence test are positively related (positively correlated) .
D) Amount of time spent engaging in mentally challenging activities and scores on a psychometric intelligence test are negatively related (negatively correlated) .