b. Krumpers from around the country travel to Los Angeles each year to display their talent and raise money for inner-city youth.
A plural verb agrees with a plural subject. In B, the subject is Krumpers. The /s/ at the end of Krumpers tells us there is more than one so it is plural. The verb that agrees with Krumpers is travel, so travel must be a plural verb. In A the subject is Tommy - he is singular. In C the subject is Lil' C or Miss Prissy. Since it's one or the other not both, the verb must be singular. In D the subject crowd is also singular because a crowd is one group even though it is made up of many people. Only singular verbs agree with singular subjects so none of these other options have a plural verb.
