Answer Happy

Consider the following knowledge base:
Provide an SLD derivation of thequery has_access(todd,library)h⁢a⁢s⁢_⁢a⁢c⁢c⁢e⁢s⁢s⁢(t⁢o⁢d⁢d,l⁢i⁢b⁢r⁢a⁢r⁢y).
Thequery has_access(mary,library)h⁢a⁢s⁢_⁢a⁢c⁢c⁢e⁢s⁢s⁢(m⁢a⁢r⁢y,l⁢i⁢b⁢r⁢a⁢r⁢y) hastwo SLD derivations. Give both of them.
Does there exist an SLD derivationfor has_access(ariel,library)h⁢a⁢s⁢_⁢a⁢c⁢c⁢e⁢s⁢s⁢(a⁢r⁢i⁢e⁢l,l⁢i⁢b⁢r⁢a⁢r⁢y)?Explain why or why not.
Explain why the set of answers to thequery has_access(X,office)h⁢a⁢s⁢_⁢a⁢c⁢c⁢e⁢s⁢s⁢(X,o⁢f⁢f⁢i⁢c⁢e) isempty.
Suppose the following clause is added to the knowledge base:
What are the answers to thequery has_access(X,office)h⁢a⁢s⁢_⁢a⁢c⁢c⁢e⁢s⁢s⁢(X,o⁢f⁢f⁢i⁢c⁢e)?