Earth is about: a) 4.6 million years old. b) 400,000 years old. c) 4.6 billion years old. d) 40 billion years old. e) 6,000 years old.

Right

C. 4.6 billion years old.

Explanation:

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.