To find the ratio of chicken wings to sandwiches, we compare the number of chicken wings (35) to the number of sandwiches (20).
The ratio can be expressed as:
\[ \text{Ratio} = \frac{\text{chicken wings}}{\text{sandwiches}} = \frac{35}{20} \]
This simplifies to:
\[ 35:20 \]
So the correct answer is 35:20.