Answer:
Option C is correct.
the scale factor is, 2
Explanation:
Scale factor(k) defined as the ratio of the length of a side of image to the length of a corresponding side of the pre image figure.
Given that the first pentagon is dilated to form the second pentagon.
Length of a side of first pentagon(pre image) = 1
And
Length of a side of second pentagon = 2
then by definition of scale factor:

therefore, the scale factor is, 2.