By the time this question had been asked, the setters were aware of their error. Earth is the fifth largest planet in the Solar System, after Jupiter, Saturn, Uranus and Neptune.
To ask for either the third, fourth, fifth or sixth largest planet in the Solar System could be considered quite risky in a League context, given that there is very little difference in size between Uranus and Neptune or between Earth and Venus. The fifth (or sixth) largest might be considered fairer, given that we all live on Earth and we should maybe know that it's sightly bigger than Venus. The mean diameter of Venus is approximately 7,520 miles, while Earth is 5.3% bigger at 7,923 miles; Uranus (31,600 miles) is just 4.6% bigger than Neptune (30,200 miles).
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