The fans crowed into the packed arena but the show was delayed for two hours.
which is not a run on sentence
a. The fans crowed into the packed arena , but the show was delayed for two hours.
b.The fans crowed into the packed arena but, the show was delayed for two hours.
c. The fans crowed into the packed arena; but the show was delayed for two hours.
d. The fans crowed into the packed arena; but, the show was delayed for two hours.