2. A relational-algebra computation on relations R(a,b) and S(b,c) is described as follows: Answer(d)d (Od-e(T1)) Try to convert the computation of Answer in terms of R and S into a Datalog rule. There are many possible Datalog rules, because, among other things, the nahes o the local varflables and the ordef or stubgoais afe arbitrary. However, at least among those without redundant subgoals correct rules will be similar except for variable names and order of subgoals. Identify, from the list below, the one Datalog rule that produces the same value for Answer as the relational algebra above O a) Answer(b) S(a,b) AND R(ba) O b) Answer(a)R(a,b) AND S(a,b) O c) Answer(d) - T1(d,e) O d) Answer(y) - R(yx) AND S(y.x)