I have never taken the JLPT before, but I feel that the only answer that fits here would be 関わらず.
金メダルはかかわらず、面白い試合ができるように一生懸命頑張ります。
Regardless of the gold medal, I’ll give it my all to make for an interesting match.
Normally you’d see に（も）関わらず, but as you have said, the は makes it sound a bit strange, but not wrong necessarily. It is just stating that the gold metal (the topic) is not having an effect on the speakers intent.
The only other response that could make any sense would be 全く, but it doesn’t quite lead into the next phrase as well, and doesn’t sound very natural to me.
As I said, I don’t have any certifications in Japanese, so take my answer with a grain of salt.
「金メダルは … 、面白い試合ができるように一生懸命頑張ります。」
If I just guess from the sentence, it will be かかわらず. However, I think this sentence is not right for a question. It should be 「メダルの色にはかかわらず」(Regardless which prize I will be in either 1st, 2nd or 3rd (gold, silver or bronze)), or 「勝敗にはかかわらず」(Regardless the result).
The following phrase (面白い試合ができるように一生懸命頑張ります) is “I will do my best for showing a nice game”, so he/she is saying that the important thing is to play a game, not a result. Therefore, although 「金メダルは …」is not right sentence from the context, but I can pick 「かかわらず」。Anyway, I think that this sentence is not right and I understand that you are confused.
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By the way, a few minutes after I wrote this, I found another possibility.
It is “のみならず”, but still the question needs to be modified a bit. If the question was “金メダル「を」「とること」….，面白い試合ができるように一生懸命頑張ります。”, then it would be “のみならず”. However, anyway this question is not right and good.
2 comments
I have never taken the JLPT before, but I feel that the only answer that fits here would be 関わらず.
金メダルはかかわらず、面白い試合ができるように一生懸命頑張ります。
Regardless of the gold medal, I’ll give it my all to make for an interesting match.
Normally you’d see に（も）関わらず, but as you have said, the は makes it sound a bit strange, but not wrong necessarily. It is just stating that the gold metal (the topic) is not having an effect on the speakers intent.
The only other response that could make any sense would be 全く, but it doesn’t quite lead into the next phrase as well, and doesn’t sound very natural to me.
As I said, I don’t have any certifications in Japanese, so take my answer with a grain of salt.
「金メダルは … 、面白い試合ができるように一生懸命頑張ります。」
If I just guess from the sentence, it will be かかわらず. However, I think this sentence is not right for a question. It should be 「メダルの色にはかかわらず」(Regardless which prize I will be in either 1st, 2nd or 3rd (gold, silver or bronze)), or 「勝敗にはかかわらず」(Regardless the result).
The following phrase (面白い試合ができるように一生懸命頑張ります) is “I will do my best for showing a nice game”, so he/she is saying that the important thing is to play a game, not a result. Therefore, although 「金メダルは …」is not right sentence from the context, but I can pick 「かかわらず」。Anyway, I think that this sentence is not right and I understand that you are confused.
​
By the way, a few minutes after I wrote this, I found another possibility.
It is “のみならず”, but still the question needs to be modified a bit. If the question was “金メダル「を」「とること」….，面白い試合ができるように一生懸命頑張ります。”, then it would be “のみならず”. However, anyway this question is not right and good.