Let 𝐴 = {2,3,6,8,9,11} and 𝐵 = {1,4,5,10,15}. Let 𝑅 be a relation on 𝐴 × 𝐵 defined by (𝑎, 𝑏)𝑅(𝑐, 𝑑) if and only if 3𝑎𝑑 − 7𝑏𝑐 is an even integer. Then the relation 𝑅 is