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