For A)
X1 = Variable (Key can be found @ Internal nodes at various levels)
X2 = Constant
X3 = Variable, We need to just check where key is present/absent, not to access Data. (A successful search means that the key exists in the database and unsuccessful means that it is not present in the database.) So Variable
X4 = Constant
For Part B) i) Write down two copies of the same table for comparison side by side. Just map B of first to A of the second copy. Those matching tuples take A of first table & B of seconds.
Content of View A
$$\begin{array}{|c|c|} \hline \textbf {A} & \textbf {B} \\\hline \text {1} & \text{3} \\\hline \text{1} & \text{4} \\\hline \text{2} & \text{5} \\\hline \end{array}$$
For Part B) ii)
Additional tuples getting inserted:
$$\begin{array}{|c|c|} \hline \textbf {A} & \textbf {B} \\\hline \text {11} & \text{7} \\\hline \text{11} & \text{8} \\\hline \text{2} & \text{6} \\\hline \text{1} & \text{11} \\\hline \end{array}$$