Igneous rocks are classified based upon their a. mineralogy and density b. density and hardness c. texture and mineralogy d. fluorescence and texture

The answer is C. texture and mineralogy

explanation:

since the crust is readily accessible, scientists have been able to perform hands-on experiments to determine its composition; studies on the more distant mantle and core have limited opportunities samples. so scientists also rely on analyses of seismic waves and gravity and as well as magnetic studies.