The blank needs to be filled with the adjective/determiner that modifies 'Solar System'. The sentence talks about the solar system to which the sun belongs, so the determiner 'a' won't be appropriate in the blank as it is used before the unspecified nouns. But, 'solar system' is specified, so 'the' is appropriate here.
'Huge' and 'typical' would limit the discussion and imply that sun is the star at the center of only huge or typical solar system, which is not correct contextually.
So, option (d) is the answer.
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