Introduction of an alien DNA into a plant cell host is done by:

The correct answer is Option (3) → Biolistics method

Option (3) Biolistics method — Correct. In the biolistics (gene gun) method, plant cells are bombarded with high-velocity gold or tungsten particles coated with the alien DNA. It suits plant cells, whose cell walls make other methods hard.

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. In another method, suitable for plants, cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun.”