Answer
(a) See the image below.
(b) Those graphs are simply transformations of their parent function $f(x)=\log(x)$
Work Step by Step
We have a function: $f(x) = c\log(x)$. To draw graphs of the family for $c=1, 2, 3, 4$ we will simply input these values and using Graphical Calculator graph them.
(a)
$f(x) = \log(x)$ (Black graph in the image)
$f(x) = 2\log(x)$ (Blue graph in the image)
$f(x) = 3\log(x)$ (Green graph in the image)
$f(x) = 4\log(x)$ (Red graph in the image)
(b) $c$ value in this case means to stretch the graph of the parent function vertically by a factor of $c$
