The process of wear and tear of the exposed country rocks is defined as

The process of gradual wear and tear of exposed country rocks due to mechanical action is known as abrasion.

It occurs when rock fragments, sand, or other particles are carried by agents like wind, water, or ice and strike against the surface of exposed rocks, causing them to erode.

Option A: Attrition refers to the wear and rounding of rock particles due to collision with one another, not the wearing of fixed country rocks.

Option C: Deflation refers to the removal of loose particles by wind, not the wearing of hard rock surfaces.

Option D: Suspension refers to the transport of fine particles in air or water, not the erosion of country rocks.

Therefore, the process of wear and tear of exposed country rocks is called abrasion.