Final answer:
When A turns one time, C will turn one time (B).
Step-by-step explanation:
In this question, we are given the values of A=10, B=20, and C=10. The ratio indicates how many times A is equal to B and C. To find how many times A is equal to C, we can set up a proportion: A/B = C/X. Cross multiplying gives us 10X = 10B, which simplifies to X = B. Therefore, when A turns one time, C will turn one time (B). So, the answer is option B. 1.