The valency of gold in AuCl is:
A. 1
B. 2
C. 3
D. 4

To determine the valency of gold in \(\text{AuCl}\), follow these steps:

1. **Identify the oxidation state of chlorine:** Chlorine typically has an oxidation state of -1.

2. **Determine the total charge of \(\text{AuCl}\):** Since the compound \(\text{AuCl}\) is neutral, the sum of the oxidation states of all elements must be zero.

3. **Let the oxidation state of gold be \( x \):** For \(\text{AuCl}\), the equation would be:
\[
x + (-1) = 0
\]

4. **Solve for \( x \):**
\[
x - 1 = 0
\]
\[
x = 1
\]

Therefore, the oxidation state of gold in \(\text{AuCl}\) is +1.

5. **Relate the oxidation state to valency:** The valency of an element in a compound is equal to its oxidation state in that compound. Here, the valency of gold in \(\text{AuCl}\) is 1.

So, the correct answer is:
**A. 1**