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Re: Mark the gramatically correct sentences
by sushmitaTG TEAM - Wednesday, 6 November 2013, 05:18 PM
  Hi,
there is an error in sentence B, as it should be "a million years".
this rules out option A and C.
with the remaining options we need to check only sentence A.
if we consider that 'when' should start with a capital ' W' (which could be a typing error), then option D is correct. otherwise, option B is the answer.