As can be seen from the figure, curve B becomes curve A, which shortens the time to reach the equilibrium, keeps the conversion rate of A unchanged when the equilibrium is maintained, and speeds up the reaction by changing the conditions and keeps the equilibrium unchanged. This reaction is a constant gas volume reaction, which can increase the pressure or use a catalyst.

After A.A.t3, systems A and B are in equilibrium, the equilibrium state of the two systems is the same, and the volume fraction of C is the same, so A is wrong;

B. The positive and negative reactions should be exothermic. When the temperature balance increases, it moves in the reverse reaction direction, and the conversion rate of A decreases, which is inconsistent with the image, so B is wrong;

At the moment of C. t 1, the system of curves A and B has not reached the equilibrium state and the reaction is going on, so VA (positive): VC (inverse) > 2: 3, that is, 3VA (positive) > 2VC (inverse), so C is correct;

D, at constant temperature, the volume of the reaction container decreases, the pressure increases, the reaction rate is accelerated, and the time to reach equilibrium is shortened, and the reaction is a reaction with constant gas volume.

The balance does not move, so reducing the volume can change curve B into curve A, so D is wrong.

So choose C.