Help me plzzz..........................................................

The best answer is that a) It drastically reduced the gene pool of the species - that's generally what bottleneck means.

b) The territorial range would be unchanged or, if anything, could grow (with reduced competition)

c) this would not be a bottleneck effect - or at least, this is not how we define it.
d) it reduced the number of genes for both dominant and recessive traits probably, so , not.