Among the given options, the correct answer is option 3, Australia. Australia has the world`s largest reserves of Uranium. Uranium is a crucial element used for nuclear fuel and nuclear weapons.

Option 1, Russia, is not the correct answer because although Russia is a major producer and exporter of Uranium, it does not have the largest reserves.

Option 2, Kazakhstan, is also a major producer and exporter of Uranium, but it does not have the largest reserves in the world.

Option 4, Jordan, does not have significant Uranium reserves compared to the other options.

Therefore, Australia is the correct answer as it has the largest reserves of Uranium, making it an important player in the global Uranium industry.