Question

is the reason for the
formation of the fold mountain
O contraction
O expansion
O compression
O reduction​

Answer 1

I think compression, please make me as Branieset

In the creation of fold mountains, Earth's crust itself is warped into folded forms. ... At a compression zone, tectonic activity forces crustal compression at the leading edge of the crust formation. For this reason, most fold mountains are found on the edge or former edge of continental plate boundaries.