​The branch of geology exploring how rocks bend in reaction to forces within the Earth’s interior is called:​

Correct option is D

The branch of geology exploring how rocks bend in reaction to forces within the Earth's interior is called structural geology.

Structural geology is the study of the deformation of the Earth's surface and subsurface, and the forces that cause that deformation. It involves the study of: 

• The geometry, distribution, and formation of rock structures 
• The composition of rock units 
• The surfaces of large rock bodies 
• The tectonic movements history of the rocks 
• Past geological events and environments that may have deformed the rocks 

Structural geology can be used to reconstruct past crustal movements and dynamics. It can also help petroleum geologists determine if oil or natural gas are trapped within rocks.