If there can be only one answer, then it's b):
a) than <ungrammatical>
b) to <considered the Standard>
c) over <yes, but not yet Standard>
d) all of the above < not possible; a) is wrong>
e) other < yes, but b) is the correct choice>
I think that a BE native speaker would nearly alway go for 'to'. But an AE native speaker would tend to use 'over'.
I'm totally agreed with philo2009, the original question was put as if it'd been taken from a test or Sth, so I don't think "Over" would be an acceptable choice here...We agree that language is what its native speakers say, but unfortunately this is not the case with what with see in lots of formal ESl tests!
Last edited by stefan_kar; 25-May-2009 at 23:13.
Bully for you!
However, you could take both forms, as long as you're not taking any test, for which you'd better use "to", just in case...Lots of luck!