Choose the most suitable option to replace the highlighted part of the sentence:
She is the only one of the candidates who have been selected.
Show answer & explanation
Correct answer: A
Explanation
This is a classic "trap" in English grammar involving the phrase "the only one of."
The General Rule: Usually, with the phrase "one of the [plural noun] who...", the relative pronoun "who" refers to the plural noun, so we use a plural verb.
Example: She is one of the candidates who have been selected. (This implies many were selected, and she is among them).
The "Only One" Exception: When you add the word "only," the focus shifts to the singular person. In the phrase "the only one of the candidates who...", the relative pronoun "who" now refers back to the singular word "one."
Result: Because the subject "one" is singular, the verb must also be singular (has).
Voice: Since the candidates are being chosen by someone else, we must keep the passive voice ("has been selected").