20. If, under perfectly competitive conditions, China (a large country) imposes a tariff on its imports of olive oil - a good which is exported by many countries, including Greece, then the following changes in Greece's consumer surplus (CS) and producer surplus (PS) are possible:

(a) CS will fall by 500, and PS will rise by 600.

(b) CS will fall by 400, and PS will rise by 300.

(c) CS will rise by 500, and PS will fall by 600.

(d) CS will rise by 400, and PS will fall by 300.

(e) none of the above