The sentence does not say whether the relative clause describes Rana alone or the scientists as a group. Which completions are standard in Rana is one of the scientists who ___ at night? Select all that apply.

الشرح

Works is standard when who attaches to the whole singular phrase headed by one, while work is standard when who refers to the embedded plural scientists. Working is non-finite and has work is malformed, so neither expresses a competing standard agreement analysis.