I would say that he is assuming that A. The US is under threat of espionage and sabotage.
A. their
Their refers to the the multiple (both means more than one) squirrels themselves
If it was HIS then it would refer to only one squirrel
If it was OUR it would mean you and me (We) had our acorns hidden
I would think exclamatory because of the exclamation point but maybe not im not sure.
Answer:
D
Explanation:
D is not a fact it is someones thought. The others are facts