Question 6 1.4 pts Consider a tree T that captures the ancestry of a group of people. Every node in the tree represents a person, and every directed edge from a node u to a node v means that vis a parent of u. We will capture this relationship in the schema parent(u, v). Select all of the true statements about the following Datalog program, where x is a constant representing a person: a(U, V, D) :-parent(U,V), D = 1 a(U, V, D) :- a(U, W, E), parent(W,V), D = E + 1 ea(U, V, D):- a(U, V, D), a(U, W, E), D