We have that the branches of the state power can have enumerated powers, namely powers that are mentioned in the constitution and implied powers, powers not directly mentioned but that are necessary for fulfilling their function. We have that the enumerated powers of the legislative branch are among others making law, setting a currency and trading with other states or entities. The enumerated powers of the executive branch include
the ability of the President to veto Congress resolutions, the power of the Treasure Department to write checks regarding national interests and among others the ability to conclude treaties and to nominate Ambassadors. Hence the correct answer is that conducting foreign relations is an enumerated power of the executive branch.
