Answer:
a. Marketopia has a comparative advantage in the production of pies.
Explanation:
The computation is shown below
As we know that the comparative advantage principle refers that the firm which has less opportunity cost in the production of a good should generate that specific good and specalize according to this
Now
for Marketopia
The opportunity cost of cookies is 18 by 30 pies = 0.6 pies
The opportunity cost of pies are 30 by 18 cookies = 1.67 cookies
For Ecolandia
The opportunity cost of cookies is 9 by 90 = 0.1 pies
The opportunity cost of pies is 90 by 9 = 10 cookies
We can see that Econlandia has the comparative advantage in cookies while on the other hand the marketopia has the comparative advantage in pies
Therefore the correct option is a.