The Old English Bulldog is extinct. To produce
  a new English Bulldog, dogs having the desired
  physical features, but not the aggressive nature
  of the old bulldogs, were mated. The result was
  a bulldog that was similar in appearance to the
  extinct bulldog, but without its fierce nature.
  Which technique was most likely used to
  develop this new variety of dog?
  (1) cloning
  (2) inducing mutations
  (3) genetic engineering
  (4) selective breeding