What Is the Meaning of the Balance of Goods and Services

What is the meaning of the balance of goods and services?  

A)  The balance of goods and services is the same as the merchandise trade balance, because services CANNOT be traded. 
B)  The balance of goods and services is equivalent to the trade balance. 
C)  The balance of goods and services is the value of all goods and services exported minus the value of all goods and services imported. 
D)  The balance of goods and services is the value of all tangible products exported minus the value of all tangible products imported.