The correct answer is d. petroleum.
The top ten oil producers countries are responsible for the production of near 68% of the total amount of oil in the world. Of those ten countries, five are Middle Eastern and Persian Gulf countries: Saudi Arabia, Iran, Iraq, United Arab Emirates, and Kuwait. This is due to the large reserves of oil that are located around the Persian Gulf. Since oil is the energetic basis of the world economy, oil has become a strategic resource, and the possession of these reserves gave a geopolitical and economic relevance to these Middle Eastern countries.
