The following organs can be regenerated in echinodermata

The correct option is "arms and disc".

Echinoderms (such as starfish, brittle stars, and sea cucumbers) are well-known for their remarkable regenerative capabilities. They can regenerate lost body parts following autotomy (self-amputation) or injury caused by predators.

Specifically, many species of starfish (Asteroidea) can regenerate complete new arms when they are damaged or lost. Furthermore, if a portion of the central disc remains intact along with an arm, the entire organism can regenerate from that piece. This process is driven by the proliferation and differentiation of undifferentiated cells (stem cells) at the wound site, allowing for the complete restoration of the complex tissue structures of both the arms and the central disc.