In silk worm, the silk glands (sericteries) are modified .......... glands.
Silkworm is the common name for the silk-producing larvae of any of several species of moths. Silkworms possess a pair of specially modified salivary glands called silk glands, or sericteries, which are used in the production of silk, which is a fibre produced by the silkworm in the production of its cocoon.
So, the correct answer is option C.