Please help me!

Known for his skilled retorts, William F. Buckley has been a leading conservative voice…
a)for closely fifty years
b)for almost half a century
c)for a virtual half century
d)for baryly less than fifty years
Which is right answer, why is it right, and why the others is wrong.
Thank you very much

This isn’t a question about the tests. Is it some other test?

b is correct