Which one of the following is not a cold current ?

The correct answer is (a), Brazil current.

The Brazil current is a warm water current that flows southward along the eastern coast of South America, from the equator to the Tropic of Capricorn. It is part of the South Atlantic Gyre, a large system of rotating ocean currents that circulates the waters of the South Atlantic Ocean.

The Benguela current is a cold water current that flows northward along the western coast of Africa, from the Cape of Good Hope to Angola. It is part of the Benguela–Angola Current System, a large system of rotating ocean currents that circulates the waters of the South Atlantic Ocean.

The Peru current is a cold water current that flows southward along the western coast of South America, from the equator to the Tropic of Capricorn. It is part of the Humboldt Current System, a large system of rotating ocean currents that circulates the waters of the Pacific Ocean.

The Labrador current is a cold water current that flows southward along the eastern coast of Canada, from the Arctic Ocean to Newfoundland. It is part of the North Atlantic Gyre, a large system of rotating ocean currents that circulates the waters of the North Atlantic Ocean.

As you can see, all of the options except (a) are cold water currents. Therefore, the correct answer is (a).