If P + Q means P is the brother of Q; P x Q means P is the wife of Q and P % Q means P is the daughter of Q then which of the following means D is the uncle of A?

The correct answer is $\boxed{A + C % B x D}$.

Here is a brief explanation of each option:

• Option A: $A % B x C + D$ means $A$ is the daughter of $B$, who is the wife of $C$, who is the daughter of $D$. This does not mean that $D$ is the uncle of $A$.
• Option B: $A x B + C % D$ means $A$ is the wife of $B$, who is the brother of $C$, who is the daughter of $D$. This does not mean that $D$ is the uncle of $A$.
• Option C: $A + C % B x D$ means $A$ is the brother of $C$, who is the daughter of $B$, who is the wife of $D$. This means that $D$ is the uncle of $A$.
• Option D: None of these.

Therefore, the correct answer is $\boxed{A + C % B x D}$.