Answer:
C
Explanation:
distance between two points formula:

where the x and y values are derived from the known points
we are given the points (2, 4) and (8, -8)
given these two points let's define each variable
x1 = 2
x2 = 8
y1 = 4
y2 = -8
we now substitute in these values into the formula

now we evaluate the expression using PEMDAS
first we do the subtraction inside of the parenthesis
8 - 2 = 6
-8 - 4 = -12
d = sqrt(6)^2 + (-12)^2
next we do the exponents
6^2 = 36
-12^2 = 144
d = sqrt( 144 + 36 )
next do the addition inside of the parenthesis
144 + 36 = 180
d = sqrt ( 180 )
finally we do the square root of 180
sqrt ( 180 ) = 13 ( rounded to the nearest whole )
d = 13