R. Foster Wynans, a reporter for the Wall Street Journal, wrote the "Heard on the Street" column, which noted rumors about various companies. Using his knowledge of what would be in his column--knowledge which was not publicly available--Wynans and a Confederate traded on the information, earning above-market returns. Which form of market efficiency does this weaken? 

a. weak-form efficiency 

b. semi-strong-form efficiency 

c. strong-form efficiency