The Tunguska Event of 1908 Was Probably Caused by a Stony

Multiple Choice

The Tunguska event of 1908 was probably caused by a stony body. Why was so little obvious evidence of meteoric impact found at the scene?

A) Evidence of a large impact like this one is highly radioactive. But during the two decades between the event and the investigation, the radioactivity had subsided.
B) The stony contents were all incinerated high in the atmosphere.
C) The stony contents all vaporized on impact, like those in the Barringer Crater in Arizona.
D) The stony contents were distributed widely over the ground. But after a few years of weathering, they became indistinguishable from ordinary rocks.