Answer:
The correct answer is letter "D": foreign stock purchases by Americans.
Explanation:
The U.S. financial account is part of the Balance of Payments of the country that reflects the domestic assets owned by foreigners and the foreign assets owned by Americans. In case the U.S. financial account increases, it means there are more foreigners owning assets locally than Americans owning assets abroad. If the account decreases, there are more Americans owning assets abroad than foreigners owning assets in the U.S.
Therefore, foreign stock purchases by Americans will be included in the U.S. financial account.