Answer:
The answer is D
Explanation:
I am not sure but the word "unsettle" means
causing anxiety or uneasiness; disturbing.
"the finale may come as an unsettling shock"
Although coal, hydrocarbons, iron ore, platinum, copper, chromium, nickel, gold and other minerals have been found, they have not been in large enough quantities to exploit. The 1991 Protocol on Environmental Protection to the Antarctic Treaty also restricts a struggle for resources.
