How do you die a happy man

Which statements describe continental crust? select the three correct answers. a-it is formed in all parts of the continents. b-it is made mostly of volcanic rock. c-it is destroyed by melting near the top of the mantle. d-it is less than 10 km thick. e-its ages ranges from very young to more than 4 billion years old.

Ineed an answer for this one (number 8)

How do you do this? i’ve marked the correct answer but i can’t seem to calculate