To determine the correct verb forms, let's break the sentence down: "One of the ladies" – The subject of the main clause is "One", not "ladies." "who sell in the premises" – The relative pronoun "who" refers to "ladies," which is plural. Therefore, the verb following it should also be plural ("sell") and not "sells." "has been asked to withdraw" – The main verb agrees with the subject "One," which is singular, so we use "has." So, "sell" agrees with "who" which refers to "the ladies". (plural subject -- plural verb) and "has" agress with "One of the ladies who sell in the premises" (singular subject -- singular verb) Thus, the correct sentence is: "One of the ladies who sell in the premises has been asked to withdraw."