Don’t we use the present perfect tense if something happened in the past and is still happening today/now?
First run in 1867 and still taking place every summer, the Belmont Stakes, a horse race for thoroughbred three-year-olds, [was] one of the oldest races in the United States.
a)was
b)is
c)were
d)are
e)has been
According to the collegeboard, B is the answer? Isn’t it supposed to be E? Thank you Mike.

Yes, the answer is most definitely B. It is one of the oldest races in the United States, currently. There’s no need for present perfect tense here.