How do i make the clone shorter?

First timer here, in everything. I took 6 clones from my plants before i put them into the flowering room, now have 4 female clones (taken at different times, so there different heights) 1 is 12" tall how do i make it shorter, so there all the same height? I'm learning a lot from you veterans, but still haven't hit a home run. Attached is a picture of my veg. room, with the clones in there.

you could bend and tie the 12 incher until the rest catch up it will make her bush out while the others catch up..