Answer
$(a)$
See the Red graphs on the image below.
$(b)$
See the Blue graphs on the image below.
$(c)$
When the value of $c$ increases the graph stretches and gets further from $y=x$ graph. When the value decreases it shrinks and gets closer to the $y=x$ graph.
Work Step by Step
$(a)$
See the Red graphs on the image above.
$(b)$
See the Blue graphs on the image above.
$(c)$ As we can see from the image above, the graph varies based on the value of denominator. The graph is in the first and third quadrants if the denominator is odd. But it is only in the first quadrant if we have even denominator. It can also be expressed as odd/even root of $x$.
When the value of $c$ increases the graph stretches and gets further from $y=x$ graph. When the value decreases it shrinks and gets closer to the $y=x$ graph.