Q76

The following table has two attributes $A$ and $C$ where $A$ is the primary key and $C$ is the foreign key referencing $A$ with on-delete cascade.

$$\begin{array}{|c|c|} \hline \textbf {A} & \textbf {C} \\\hline \text {2} & \text{4} \\\hline \text{3} & \text{4} \\\hline \text{4} & \text{3} \\\hline \text{5} & \text{2} \\\hline \text {7} & \text{2} \\\hline \text{9} & \text{5} \\\hline \text{6} & \text{4} \\\hline \end{array}$$

The set of all tuples that must be additionally deleted to preserve referential integrity when the tuple $(2, 4)$ is deleted is: