Which set of ordered pairs represents a function?
{(−5,−9),(−7,−9),(−5,−7),(−8,6)}
{(−1,6),(0,−3),(5,−9),(−1,3)}
{(1,2),(−6,2),(3,9),(5,3)}
{(−3,9),(2,7),(2,−4),(1,5)}
{(−5,−9),(−7,−9),(−5,−7),(−8,6)}
{(−1,6),(0,−3),(5,−9),(−1,3)}
{(1,2),(−6,2),(3,9),(5,3)}
{(−3,9),(2,7),(2,−4),(1,5)}