On Sunday, the 2012 Formula 1 World Championship will finally be decided at the Brazilian Grand Prix. The result will end up with a three-time world champion but the question is, which one? Sebastian Vettel leads Fernando Alonso by 13 points but, with Vettel having retired from last year's race in Interlagos, the pair know the championship could go either way. Approaching the season finale, we assess the chances of the two title rivals...