A, a teacher at Mapa High School, having gotten mad at X, one of his pupils, because of the latter's throwing paper clips at his classmates, twisted his right ear. X went out of the classroom crying and proceeded home located at the back of the school. He reported to his parents, Y and Z, what A had done to him.

Y and Z immediately proceeded to the school building and because they were running and talking in loud voices, they were seen by the barangay chairman, B, who followed them as he suspected that an untoward incident might happen. Upon seeing A inside the classroom, X pointed him out to his father, Y, who administered a fist blow on A, causing him to fall down. When Y was about to kick A, B rushed towards Y and pinned both of the latter's arms. Seeing his father being held by B, X went near and punched B on the face, which caused him to lose his grip on Y. Throughout this incident, Z shouted words of encouragement at Y, her husband, and also threatened to slap A.

Security guards of the school arrived, intervened and surrounded X, Y and Z so that they could be investigated in the principal's office. Before leaving, Z passed near A and threw a small flowerpot at him but it was deflected by B.

(a) What, if any, are the respective criminal liabilities of X, Y, and Z?
(b) Would your answer be the same if B were a barangay tanod only? (2001 BAR)