The correct answer is D. You are said to have done that.
The sentence “They say that you did that” can be interpreted in a few different ways. It could mean that someone is telling you to do something, or that someone is advising you to do something. However, the most likely interpretation is that someone is saying that you did something, even if you didn’t actually do it. This is because the word “say” can be used to mean “tell” or “report,” as well as “speak.” In this case, the speaker is reporting that someone else has said that you did something.
The other options are not as likely interpretations of the sentence. Option A, “You are told to do that,” is possible, but it is less likely than option D. Option B, “You are advised to do that,” is also possible, but it is even less likely than option A. Option C, “You did that said by them,” is not a possible interpretation of the sentence.
In conclusion, the correct answer to the question “They say that you did that” is D. You are said to have done that.