The unit for concentration equilibrium constant for the following reaction is _________2A + 9B ←→7C + 4D

• A. \((\frac{mol}{dm^3})\)2
• B. \((\frac{mol}{dm^3})\)9
• C. \((\frac{mol}{dm^3})\)-4
• D. \((\frac{mol}{dm^3})\)-3