Which of the below-mentioned wild cabbage variety was selectively bred for its larger leaves?

Kale has descended from the ancestral stock of wild cabbage. It is a result of the artificial selection for larger leaves. 

Early farmers started cultivating wild cabbage thousands of years ago. They selectively bred the crop with desired characteristics like large leaves, sterile flowers, shorter stems, swollen parts, etc., to obtain different crop varieties like kale, cauliflower, cabbage, kohlrabi, etc. from the same ancestral stock.