Which is not a method used in genetic engineering?

a gene is removed.

a gene is inserted to make a mutation inactive.

a synthetic gene is created.

Third option is correct.

Explanation:

Genetic engineering is a method of artificial manipulation, modifications and recombination of genes to modify the population of any organisms.

In this type pf engineering, genes get inserted to make a mutation inactive or a gene is removed.

But no synthetic gene is created by this process.

Hence, third option is correct.