A

Step 1: For a ray of light passing from a liquid to air, where it suffers zero deviation, the angle of incidence (i) is equal to the angle of refraction (r) at the air interface due to the conditions of zero deviation.
Step 2: Use Snell's law: \( n_{liquid} \sin(i) = n_{air} \sin(r) \). Given that \( n_{air} = 1 \), we have: \( n_{liquid} \sin(i) = \sin(i) \).
Step 3: For zero deviation, it implies \( \sin(i) = 1\), which means \( i = 90^\circ \). However, we typically relate angles in the question to known angles.
Step 4: Considering the requirement to express the answer as \( i = k \cdot 9^\circ \), we infer \( k = 1 \). Therefore, the answer is \( 1 \cdot 9^\circ \) or 9 degrees.
Therefore, the angle of incidence i is effectively related to option A which is defined as per standard knowledge.