Which one is considered the best quality silk?

Central Silk Research and Training Institute $(CSRTI)$ is located at:

The largest silk-producing state of India is:

The zoological name of the common silkworm is:

Silk is the secretion of

$A$ : Sericin is a gummy substance which is usually retained in case of silk till the yarn or fabric stage.
$R$ : Sericin gives protection during processing.