Which of the following statements is true? a) minerals such as sodium chloride are priced lower because they are necessary for life, while decorative metals such as gold for jewelry making are priced higher because they are luxuries. b) the trend is moving away from using surface mines, because they cause so much collateral air and water pollution. c) a mineral deposit may become reclassified as a mineral reserve if the price of the element or compound rises due to scarcity. d) environmental regulation lowers the cost of mining.

bc blah

explanation:

bc blah

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.