Alien DNA can be introduced in the animal host cell by:

The correct answer is Option (2) → Using micro injection

Option (2) Using micro injection — Correct. In micro-injection, recombinant DNA is injected into the nucleus of an animal cell.

NCERT Extract:
Cloning Vectors – “… Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 420C (heat shock), and then putting them back on ice. This enables the bacteria to take up the recombinant DNA. This is not the only way to introduce alien DNA into host cells. In a method known as micro-injection, recombinant DNA is directly injected into the nucleus of an animal cell.”