Answer:
The percent of change 200%.
Hope that helps!
Step-by-step explanation:
we are given

where
F is the number of board feet
d is the diameter (in inches) of the log
Since, we have to minimize F
so, firstly we will find it's derivative


now, we can set it to 0
and then we can solve for d


so, we get diameter as
..............Answer
C. 5 is the correct answer