In case of sentence which starts with of of three rules are to be followed as given below
Rule one : one of is a singular term and commonly used to refer to a noun or a pronoun.
Rule Two : any nous or pronoun to be used after one of should be in plural form( to talk about one out of many things its grammatically correct use plural form)
Rule Three : according to subject verb agreement rule, singular subjects should take singular verb here we are talking about one hence it is singular and hence is should be used
