Answer:
The answer is the second table (the one with B and C.)
Step-by-step explanation:
You know this, because the other tables are just based on patterns and the x and y values have nothing to do with each other. However, for the second table, the b value times 3 equals the c value. This is how you know the table shows a proportional relationship, and this is key to solving this problem.
Here's an image that helps demonstrate this idea: