Palladium, a Soft Shiny Silvery-White Metal, Is One of Six

Palladium, a soft shiny silvery-white metal, is one of six platinum group metals and is relatively rare. It was discovered in 1803 by William Hyde Wollaston. Palladium often replaces platinum since it is cheaper, harder and lighter. It can be drawn into wire or hammered out into sheets, it is often mixed with gold for "white gold" jewelry. Palladium can also be used to make surgical instruments. Automobile manufacturers need the world's palladium for catalytic converters. Along with gold, silver, and platinum, palladium is a precious metal owned and traded by investors.
Palladium mining is an intricate process because it is spread out under the earth's surface. Mining palladium uses mechanical extraction methods that simplify the process. Makes it easier to get down into the Earth's crust. The reserves in the upper portions of the crust is becoming depleted, so miners have to dig deeper. Most palladium is in Russian, North America, South Africa, and South America. The largest North American palladium mine - Montana's Stillwater mine - is located in the United States. In South Africa, there is the largest proportion of palladium and platinum resource located mainly at the Bushveld Igeneous Complex.
What is the main idea of this passage?

A) Worldwide reserves of palladium are depleted, leading to deeper mines and higher prices.
B) Discovered in 1804, palladium, a precious metal, is used for jewelry and industry, and is mined in North and South America, Russia, and South Africa.
C) The Palladium mines in North America and South Africa produce most of the world's supply of this precious metal.
D) Mechanical extraction of palladium is a simple process and has made it easier to extract the metal from the earth.