The correct answer is: Only argument I is strong.
Argument I is strong because it provides a clear and convincing reason why there should be a cap on the maximum number of contestants for parliamentary elections in any constituency. The argument states that this will make the parliamentary elections more meaningful as the voters can make a considered judgement for casting their vote. This is a valid reason because it is in the interest of democracy that voters have a clear choice between candidates and are able to make an informed decision about who to vote for.
Argument II is weak because it does not provide a clear and convincing reason why there should be no restrictions on the number of contestants for parliamentary elections. The argument simply states that in a democracy any person fulfilling the eligibility criteria can contest parliamentary elections and there should be no restrictions. This is not a valid reason because it does not take into account the interests of voters. It is possible that having too many contestants in a constituency could make it difficult for voters to make a considered judgement about who to vote for.
In conclusion, only argument I is strong.