The correct answer is option 3, Kuroshio. A cold ocean current is a flow of cold water from polar regions towards the equator. In this question, we are asked to identify which option is not a cold ocean current.

Option 1, California, is a cold ocean current that flows along the west coast of North America. Option 2, Oyashio, is a cold ocean current that flows along the eastern coast of Japan. Option 4, Canaries, is a cold ocean current that flows along the coast of Northwest Africa.

Therefore, the answer is option 3, Kuroshio, as it is a warm ocean current that flows along the eastern coast of Japan, opposite to the cold Oyashio current.