Let the capacity of the tank be x L

As per the question,

Quantity of water emptied by the leak in 1 h $=\frac{\mathrm{x}}{10}\mathrm{L}$

And to empty 4L in 1h$=\frac{\mathrm{x}}{15}$

Quantity of water filled by the tap in 1 min = 4L

∴1h=4L

As per the question,

$$\begin{gathered} \frac{\mathrm{x}}{10}-\frac{\mathrm{x}}{15}=240 \\ \Rightarrow \frac{3\mathrm{x}-2\mathrm{x}}{30}=240 \\ \Rightarrow \frac{\mathrm{x}}{30}=240 \\ \therefore \mathrm{x}=240\times 30=7200\mathrm{L} \end{gathered}$$

Hence option D is correct.