The rearing of silkworms for obtaining silk is called as:

Explanation:

The correct answer is option B.

The method of rearing silkworms for the purpose of primarily obtaining silk is called sericulture.

Meanwhile pisciculture is the method of rearing as well as further breeding of fishes to obtain various products, mainly in the form of diet.

Polyculture is the method of cultivating more than one crop on the same land and in the same season.

Arboriculture is the method of cultivation of shrubs (small plants) as well as trees.

Final Answer:

Hence, the correct answer is option B i.e. the activity of rearing silkworms for obtaining silk is called sericulture.