Why did western nations become interested in saudi arabia during the twentieth century?

saudi arabia abandoned islamic law.
the nation set up european-style courts.
oil was discovered on the arabian peninsula.

Oil was discovered on the Arabian peninsula.

Explanation:

The proven oil reserves in Saudi Arabia are the second largest in the world, just behind Venezuela's reserves. They are estimated at 267 billion barrels (42 × 10 ^ 9 m3) including 2.5 billion barrels in the Saudi-Kuwaiti Neutral Zone. This is about one fifth of the total of the world's conventional oil reserves. Although Saudi Arabia has around 100 oil and gas fields, more than half of its oil reserves are found in only eight giant oil fields, including the field of Ghawar Field, the largest oil field in the world with an estimated of 70 billion barrels (11 × 10 ^ 9 m3) of the remaining reserves. Saudi Arabia maintains the world's largest crude production capacity, estimated at around 11 million barrels per day (1.7 × 10 ^ 6 m3 / d) by mid-2008 and has announced plans to increase this capacity to 12, 5 million barrels per day (2.0 × 10 ^ 6 m3 / d) in 2009.

c is the awnser that best describes the role of the english monarchy in its consitution