Which of the following does not belong to others in the group XZ, MN, PQ, BC, ST?

Option 4 : XZ

[ src="//storage.googleapis.com/tb-img/production/20/02/Capture_009.PNG" style="width: 587px; height: 130px;">

The pattern followed here is,

[ alt="F1 A.M 24.1.20 Savita D2" src="//storage.googleapis.com/tb-img/production/20/02/F1_A.M_24.1.20_Savita_D2.png" style="width: 61px; height: 56px;">

[ alt="F1 A.M 24.1.20 Savita D3" src="//storage.googleapis.com/tb-img/production/20/02/F1_A.M_24.1.20_Savita_D3.png" style="width: 61px; height: 58px;">

[ alt="F1 A.M 24.1.20 Savita D4" src="//storage.googleapis.com/tb-img/production/20/02/F1_A.M_24.1.20_Savita_D4.png" style="width: 60px; height: 56px;">

[ alt="F1 A.M 24.1.20 Savita D5" src="//storage.googleapis.com/tb-img/production/20/02/F1_A.M_24.1.20_Savita_D5.png" style="width: 61px; height: 55px;">

[ alt="F1 A.M 24.1.20 Savita D6" src="//storage.googleapis.com/tb-img/production/20/02/F1_A.M_24.1.20_Savita_D6.png" style="width: 61px; height: 56px;">

All follow the same pattern, except ‘XZ’.

Hence, XZ does not belong to the group.