Figured this out! Intramolecular reactions are always much faster than intermolecular reactions. The OH acts as a nucleophile and attacks the double bond. Counting the distance between the OH and the end of the double bond will yield 6 membered ring. Also the 6 membered ring is the most stable as it can form the chair conformation.
Hi there! This reaction will result to the bonding of the -OH group to the most substituted C in the original C=C. So we will end up with a six membered ring (along with O). So we will choose between C or D. If we will count the C in the starting material, we have 9 Cs so the product should also contain 9 carbons as well so the correct answer is IV. Hope that clears things up!