The Democratic Republic of the Congo (Option 3) is indeed the world`s largest producer of cobalt, supplying about three-fourths of the global output. This makes it crucial for the manufacturing of batteries used in electric motor vehicles.

Looking at the other options:

Argentina (Option 1) is more known for its agricultural products, and while it does have some mining, it isn`t a significant source of cobalt.

Botswana (Option 2) is rich in diamonds and minerals but is not recognized as a main player in global cobalt production.

Kazakhstan (Option 4) is a significant global producer of uranium and has diverse mineral resources, but cobalt production isn`t a major focus.

Therefore, Option 3 - The Democratic Republic of the Congo, correctly identifies the largest producer of cobalt in the world.