If we change the value of the slope of the equation by 6, the line will be steeper, that is, it will have a larger angle regarding the x-axis.
We can see this because the value of 4 is actually the value for the slope. With a slope of 6, the value of the slope increases. We can see this graphically:
This is sketched in the graph. The red line is the equation y = 4x + 5, and the blue line is the equation y = 6x +5. The line in blue has a greater angle with respect to the x-axis. It is steeper.
Then the option is STEEPER.