Answer: Option (D)
Explanation: The continental crust is estimated to be about 2 billion years old measured by the U₂₃₈-Pb₂₀₆ dating method, whose life is about 4.5 billion years. It is comprised of about 55-60% of SiO₂ and 15-20% of AL₂O₃, and are comparatively less denser than the oceanic crust.
The density of the continental crust is about 2.85 g/cm³ and its thickness is about 35-40 km. In the mountain ranges like the Himalayas, its thickness ranges from about 40-80 km. The continental crust is created and destroyed due to the plate tectonic movement, thereby conserves the total crust of the earth.
Hence the correct answer is (D)
