Which of the following is used in somatic hybridization to fuse two somatic protoplasts?

The correct option is B Polyethylene glycol
Polyethylene glycol helps in cytoplasmic fusion. It is used in the somatic hybridization technique to fuse two protoplasms of two different species.

Pectinase digests pectin in the cell wall and colchicine is used as a mitotic poison.

Colchicine is an important medicinal compound used to prevent gout attacks. IAA (Indole-3-Acetic Acid) is the abundant and well known plant hormone of the auxin class. IAA is produced in the apical bud of and young leaves of plants and is known to be an inducer of cell division and elongation.

So, the correct option is 'Polyethylene glycol'.