The correct answer is - the introductory text in the sentence cannot stand alone.
The colon after 'including' should be removed because it is completely unnecessary. The word 'including' acts as a colon of sorts, so using both is redundant. You can either delete the colon and leave the sentence as is, or delete the word 'including' and add a colon, but not both.
it's D to expose the enviromental threats posted by ridgetop development
D. The thesis. It's going be your statement that you're trying to prove.
