The Estimated Impact Energy of the Object That Produced the Meteor

The estimated impact energy of the object that produced the Meteor Crater in Arizona, in terms of explosive power (tons of TNT equivalent, a somewhat dubious and frightening scale!) , is

A) greater than 1000 megatons.
B) about 1 megaton.
C) about 20 megatons, similar to the most powerful hydrogen bombs.
D) similar to the first nuclear weapons-less than 10 kilotons.