Question: What historical regions does the city where MA'ADEN's corporate headquarters are located belong to?

<P0-S0> Riyadh (/rɨˈjɑːd/; Arabic: الرياض‎ ‎ "ar-Riyāḍ" ] ) is the capital and most populous city of Saudi Arabia. <P0-S1>  It is also the capital of Riyadh Province and belongs to the historical regions of Najd and Al-Yamama. <P0-S2>  It is situated in the center of the Arabian Peninsula on a large plateau and home to more than six million people. <SEP> <P1-S0> Corporate headquarters is the part of a corporate structure that deals with important tasks such as strategic planning, corporate communications, taxes, law, marketing, finance, human resources, and information technology. <P1-S1>  Corporate headquarters takes responsibility for the overall success of the corporation and ensures corporate governance. <P1-S2>  It is sometimes referred to as the head office, which is the location where the executives of a business work and where many of the key business decisions are made. <P1-S3>  Generally, corporate headquarters acts as a core when the business is operating. <P1-S4>  The corporate headquarters includes: the CEO (chief executive officer) as a key person and their support staff such as the CEO office and other CEO related functions; the "corporate policy making" functions: Include all corporate functions necessary to steer the firm by defining and establishing corporate policies; the corporate services: Activities that combine or consolidate certain enterprise-wide needed support services, provided based on specialized knowledge, best practices, and technology to serve internal (and sometimes external) customers and business partners; the interface: Reporting line and bi-directional link between corporate headquarters and business units. <P1-S5>  Most other divisions and branches report to the corporate headquarters and staff may visit there periodically for training or other instructions" (Kimberly: 2014: 22). <P1-S6>  The corporate services are often relocated into a separate legal entity called shared services center. <P1-S7>  Research shows that the city in which a company is headquartered has a significant influence on the company's activities, including its business practices and its corporate philanthropic giving. <SEP> <P2-S0> MA'ADEN (Saudi Arabian Mining Co.) is a diversified mining company, active in gold base metals mining and infrastructure industry. <P2-S1>  The company is structured with corporate headquarters in Riyadh with several subsidiaries. <P2-S2>  Ma'aden was formed as a Saudi joint stock company on 23 March 1997 for the purpose of facilitating the development of Saudi Arabia’s mineral resources. <P2-S3>  It is the largest mining company in Saudi Arabia. <P2-S4>  The Saudi government still owns 50% of its shares while the remaining 50% are listed in Tadawul (Stock Market). <SEP> <P3-S0> For many years the Spanish monarchy and the dictatorships which followed—Primo de Rivera and Franco—maintained the position that Spain was a unified nation, the legacy of the Roman province, Hispania. <P3-S1>  In reality, Spain (formerly known as the Spains) is and has long been a cluster of different territories with their own systems. <P3-S2>  Currently, Spain is divided into eighteen autonomous entities, which are themselves composed of fifty provinces. <P3-S3>  Seven of those eighteen autonomous entities are officially designated as "nationalities", while the rest are defined as regions, historical regions, communities and historical communities. <P3-S4>  There are many proponents of this confederacy, however it does carry certain historical problems. <P3-S5>  Just as neither modern nor historical Spain were a single unit, the modern divisions also do not really work in the past. <P3-S6>  Nonetheless, modern Spain is more easily understood when one first understands the differences which underlie its current divisions.