What evidence is preserved to indicate that a large meteorite impact occurred at the end of the mesozoic?

High concentrations of iridium, of extraterrestrial origin, shocked quartz, evidence of fire, tsunami deposits, a fern spore spike, indicating colonization of disturbed landscapes by ferns, and the large Chicxulub impact structure in the Yucatan, dated to c 65 mya--about the same time as the end of the Mesozoic.

The answer is b im not sure 

Nation of conflicting ethnic groups