Convert each letter to its position number and check the gap between letters within each group. ZWT: Z(26)-W(23)-T(20), each step is -3. HEB: H(8)-E(5)-B(2), each step is -3. TQN: T(20)-Q(17)-N(14), each step is -3. But BYW: B(2)-Y(25)-W(23) does not follow a steady -3 pattern from B to Y. So BYW breaks the rule, option (3).