First we study the $B^0$ decay to $D^0 \bar D^0 K^0$ and make predictions for the $D^0 \bar D^0$ invariant mass distribution within the chiral unitary approach in which the X(3720) resonance are dynamically generated. From the shape of the distribution, the existence of the resonance below threshold could be induced. We also predict the rate of production of the X(3720) resonance to the $D^0 \bar D^0$ mass distribution with no free parameters. Then we study the $B^+$ decay to $D^0 \bar D^0 K^+$ and compare with experimental data. From our results, we find a good agreement with the data within the present errors. It is noticeable to find that the $B^0$ decay to $D^0 \bar D^0 K^0$ is better suited to study the X(3720) resonance since there is no tree level $D^0 \bar D^0$ production and this forces $D^+ D^-$ decay to $D^0 \bar D^0$ transition to intervene and make $D^0 \bar D^0$ at the end. Future experiment would be very helpful in the search of this elusive state, and as a further test of the nature of the X(3720) resonance.