The logic here is
$$\left(14\times15\right)-1=209$$
$$\left(19\times20\right)-1=379$$
$$\left(26\times27\right)-1=701$$
$$\left(29\times30\right)+1=871$$
All the number pairs except 29 - 871 are in the form of N :Â [N x (N + 1)] - 1.
$$\therefore\ $$29 - 871 is the odd number pair among the given number pairs.
Hence, the correct answer is Option D
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