Question: What is the capital city of the least populous nation where Himalayan Butterfly Bush grows?
Sentence (from "Buddleja crispa"): Buddleja crispa, sometimes called the Himalayan Butterfly Bush, is native to Afghanistan, Bhutan, North India, Nepal, Pakistan and China (Gansu, Sichuan, Xizang), where it grows on dry river beds, slopes with boulders, exposed cliffs, and in thickets, at elevations of 1400–4300 m.
Relevant evidence: Yes