Could you elaborate on the question: "Which country is the best friend of Saudi Arabia?" Given that Saudi Arabia and the United States have been described as close strategic allies and partners, does this automatically mean that the United States is Saudi Arabia's best friend? Or could there be other countries that have an equally strong or stronger relationship with Saudi Arabia? What factors might be considered when determining a country's status as a "best friend" to Saudi Arabia? And how does Saudi Arabia define friendship in international relations? Would it be primarily based on economic ties, political alliances, cultural affinities, or a combination of these factors?