50. For C.ID = 10, all tuples from $A \cup B$ satisfies the join condition, hence 5 tuples (union of A and B has only 5 tuples are 2 of them are repeating for Shreya and Rohit) will be returned. Now, for C.ID = 99, A.ID = 99 and A.ID = 98 (for A.ID = 98, we need to assume A ∪ B, has the same schema s A as told in the question) satisfies the condition A.ID>40, and hence two tuples are returned. So, number of tuples = 5 + 2 = 7.
The output will be:
$$\begin{array}{llllll}\\\hline \textbf{Id} & \textbf{Name} & \textbf{Age} & \textbf{Id} & \textbf{Phone} & \text{Area} \\\hline \text{12} & \text{Arun}& \text{60} & \text{10}& \text{2200} & \text{02}\\ \text{15} & \text{Shreya}& \text{24} & \text{10}& \text{2200} & \text{02}\\ \text{99} & \text{Rohit}& \text{11} & \text{10}& \text{2200} & \text{02}\\ \text{25} & \text{Hari}& \text{40} & \text{10}& \text{2200} & \text{02}\\ \text{98} & \text{Rohit}& \text{20} & \text{10}& \text{2200} & \text{02}\\ \text{99} & \text{Rohit}& \text{11} & \text{99}& \text{2100} & \text{01} \\ \text{98} & \text{Rohit}& \text{20} & \text{99}& \text{2100} & \text{01}\\\hline \end{array}$$
Correct Answer: $A$