A prevailing current theory to explain extinction event that deprived the modern world of dinosaurs is tha?

While dinosaurs were in a decline in the late Cretaceous - possibly linked with climate and habitat changes due to the break up of Pangea, and also possible related to the increaced vulcanism ociated with active plate spreading ( which would have had large scale climate effects) the theory of Asteroid or Cometary impact as the cause of the great extinction at the end of the Cretaceous, popularised by Louis Alveres (e.g. in "T Rex and the crater of doom") is the one to pick from your multiple choice answers.