After a three-unit leftward translation, the transformed function passes through (-6, y). Since the original point is (-3, y), the value of y remains the same, which is 3. The correct answer is (b) 3.
Let's break down the steps:
1. Original Point: The original point is (-3, y).
2. Translation Left: When the function is translated three units left, we subtract 3 from the x-coordinate of the original point. So, the new point is (-3 - 3, y) = (-6, y).
3. Determine y: The y-coordinate remains the same after the leftward translation. Therefore, the value of y for the transformed function is the same as in the original point.
So, the value of y is 3.
Therefore, the correct answer is b. 3.