Answer : The correct option is, (C) 
Step-by-step explanation :
As we know that tree trunk is in cylindrical shape. So, we are applying volume of cylinder to calculate the volume of tree trunk.
Formula used :

where,
V = volume of tree trunk
r = radius of tree trunk = 3 feet]
h = height or length of tree trunk = 8 foot
Now put all the given values in the above formula, we get:



Therefore, the volume of tree trunk is, 