I think it’s 1 Trillion. If you want to match most often the answer is obviously 1-Million as the ‘a lot of money’ standard answer. Once you’re willing to ask for more than that, 1 Billion is in a strange place where it’s obviously a lot but also obviously ‘not enough’ in the sense that there are many who would be richer than you, whereas 1 Trillion is clearly ‘enough’ and the only plausible point above a billion, so I don’t think it’s that much less likely once you know the person knows roughly the orders of magnitude involved and the word “trillion”. If the person really is random then 1 Billion becomes more reasonable, but I think it has to be ‘average American’ level random.
I think it’s 1 Trillion. If you want to match most often the answer is obviously 1-Million as the ‘a lot of money’ standard answer. Once you’re willing to ask for more than that, 1 Billion is in a strange place where it’s obviously a lot but also obviously ‘not enough’ in the sense that there are many who would be richer than you, whereas 1 Trillion is clearly ‘enough’ and the only plausible point above a billion, so I don’t think it’s that much less likely once you know the person knows roughly the orders of magnitude involved and the word “trillion”. If the person really is random then 1 Billion becomes more reasonable, but I think it has to be ‘average American’ level random.