Answer:
A - dollar-denominated deposits at any foreign bank or foreign branch of an American bank.
Explanation:
As the answer briefly explains, Eurodollars are dollar deposits at foreign banks or overseas branches of American Banks. Given that they are not in the U.S, this funds are not subject to regulation by the FRB (Federal Reserve Board). If, for example, an individual has 100 dollars in the U.S branch of a bank and then 100 dollars in an European branch of the same bank, those 100 dollars would not be subjected to the same regulations and they would be called "Eurodollars".