Which disease is caused by viroid?

Correct option is A

✅ Correct option: (a) Potato spindle tuber
· Potato spindle tuber disease is caused by PSTVd, a viroid — the smallest infectious pathogen.
❌ Other options:
· (b) Wheat streak – Caused by Wheat streak mosaic virus.
· (c) Sterility mosaic – Transmitted by mites; caused by virus-like particles, not viroid.
· (d) Fig mosaic – Caused by Fig mosaic virus.