The most accurate investigation into how access to oil impacts the actions of countries in Southwest Asia would be:
Oil has led to some cooperation between countries in the region, but it has also been a source of conflict and competition.
This option acknowledges the multifaceted nature of how oil impacts the geopolitical dynamics in Southwest Asia. While there are instances of conflict over oil, there are also cases where oil has facilitated cooperation among countries. This complexity provides a more nuanced perspective than simply attributing conflicts solely to oil or suggesting that resource-sharing agreements uniformly benefit all countries involved.