(A) AB: row1 = (12+63, 36+81, 0+72) = (75, 117, 72); row2 = (4+21, 12+27, 0+24) = (25, 39, 24). Matches (II).
(B) P+Q row1 = (75, 117, 72); row2 = (25, 49, 24). Matches (III).
(C) Subtraction: row1 = (75, 117, 72); row2 = (35, 39, 24). Matches (I).
(D) row1 = (75, 127, 72); row2 = (25, 49, 24). Matches (IV).