Which of the following complex has a possibility to exist as meridional isomer?

<p>Meridional (mer) isomerism is a type of geometrical isomerism found specifically in octahedral complexes, where three identical ligands occupy a meridian plane. Thus, it requires at least three identical bidentate or monodentate ligands.</p> <p>Given the options, the complex that could potentially exist as a meridional isomer is :</p> <p>Option D : $[\mathrm{Co}(\mathrm{NH}_{3})_{3}(\mathrm{NO}_{2})_{3}]$</p> <p>In this complex, there are three $\mathrm{NH_3}$ and three $\mathrm{NO_2}$ ligands, allowing it to form a meridional configuration where either all three $\mathrm{NH_3}$ or all three $\mathrm{NO_2}$ ligands lie along a meridian plane.</p>