Which of the following statement(s) is/are true for the gravity model to explain trade ?
I. It is used in the bilateral context.
II. It was developed by Jan Tinbergen in 1962.
III. It takes into account the distance among the trading nations.
Select the correct answer from the code below :
1
II and III are true.
2
Only I and III are true.
3
Only II is true.
4
All the three above are true.