Read this and answer the question. If the question is unanswerable, say "unanswerable".

The country is a significant agricultural producer within the EU. Greece has the largest economy in the Balkans and is as an important regional investor. Greece was the largest foreign investor in Albania in 2013, the third in Bulgaria, in the top-three in Romania and Serbia and the most important trading partner and largest foreign investor in the former Yugoslav Republic of Macedonia. The Greek telecommunications company OTE has become a strong investor in former Yugoslavia and in other Balkan countries.

What is the smallest in the Balkans for Greece?
unanswerable