The issue is...  Those towers turned to dust.  If it was explosives, there would have been 10 times the debris (at least!), the seismic footprint would have been vastly bigger, and the heat would have made it so that no one could have wandered around on top of things within minutes.

My highest probabilities - by a very high margin! - is DEW's.

I recommend reading:  Where Did the Towers Go?  https://drjudywood.com/wp/book/