Answer:
Correct answer is 15 000 years ago.
Step-by-step explanation:
The first option is correct answer as we have material evidences in the region of Bluefish Caves, that dates back to the period even as old as more than 20 000 years.
That is why all other options are false. Especially second option as in that period this territory was inhabited by numerous tribes. And of course, remaining two option are not correct also, as we said that it was inhabited much before that period.