Looking on the internet deeply has found these results:

Who said that? is the most popular phrase on the web.

Who said this? 115,200,000 results on the web	Who said that? 143,900,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
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Who said this?

115,200,000 results on the web

Who said that?

143,900,000 results on the web

More popular!