Coincidence
No one really knows why coincidences occur but they are always interesting even if they may be creepy sometimes. This OP spotted something surprising while in class and had to take a picture just in case no one would believe them later on. As you can see, there are three girls with identical colored hair wearing the same colored top sitting in the same row one behind another!
Could they have planned it? Was the picture staged? We are as bamboozled as you guys because seriously, what are the chances of something like this happening naturally? Are there any statisticians in the house who can answer our doubts?