Which rice variety is widely recognised for tolerance to flash floods/submergence?

Correct option is A

· Swarna-Sub1 is a version of mega variety Swarna into which the Sub1 (Submergence-1) gene has been introgressed via marker-assisted breeding, giving tolerance to complete submergence from flash floods for about 10–14 days.
· for flood-prone areas list Swarna-Sub1 among the recommended flash-flood tolerant rice varieties.
Why other options are wrong
· (b) Pusa Basmati 1121 – known for extra-long grains and export quality, but not specially bred for flood tolerance.
· (c) Pusa Basmati 1979 – herbicide-tolerant basmati, not specifically flood tolerant.
· (d) MTU 1001 – a high-yielding variety but no specific flash-flood tolerance trait is highlighted for it.