Recent research indicates that increased consumption of fruits and vegetables by middle-aged people reduces their susceptibility to stroke in later years. The researchers speculate that this may be because fruits and vegetables are rich in folic acid. Low levels of folic acid are associated with high levels of homocysteine, an amino acid that contributes to blocked arteries. Which one of the following statements is most strongly supported by the information above? ['A decreased risk of stroke is correlated with increased levels of folic acid.', 'An increased propensity for blocked arteries is correlated with decreased levels of homocysteine.', 'Stroke is prevented by ingestion of folic acid in quantities sufficient to prevent a decline in the levels of homocysteine.', 'A decreased propensity for blocked arteries is correlated with low levels of folic acid.']