Excessive swelling at intersegment of larvae of silkworm, where larvae looks like bamboo cane with distinct nodes is caused by

Answer: Option A

Excessive swelling at inter-segment of larvae of silkworm, where larvae look like bamboo cane with distinct nodes is caused by Virus.
It is caused by Bombyx mori Nuclear Polyhedrosis Virus (BmNPV) of the family Baculoviridae.
The diseased larvae in the final stage show pronounced swellings at the intersegment resulting in bamboo cane-like appearance of larvae with distinct nodes.