If you alter the "c" value, then you are moving the graph up (or down if c is negative).
Since you are shifting the graph up, the y-intercept ("h" in your graph) will move up.
Since you are shifting the graph up, then the maximum will shift up.
Since you are shifting the graph up, then the x-intercept ("t" in your graph) will increase (move to the right).
Answer: K