Which algebraic expression is a polynomial? 3m2n – StartFraction 2 m Over n EndFraction + StartFraction 1 Over n EndFraction StartFraction 2 m n Over 5 EndFraction – StartFraction StartRoot m EndRoot Over 4 EndFraction + 4m5 StartFraction 4 m cubed Over n squared EndFraction – 3mn5 + StartRoot 8 EndRoot 7mn + StartFraction 3 m Over 2 EndFraction + StartFraction 5 n Over 4 EndFraction