Answer:
5 cubic units
Step-by-step explanation:
If each cube represents 1 cubic unit, then the volume will be the number of cubes to make the figure. When you count, there are 5 cubic units. The volume is 5.
In the first series, the summation applies to the whole (2n+3) inside
the parentheses, so the 3 gets summed up 5 times.
But in the second one, the summation only applies to the 2n , so
the 3 is only added after the summation is finished.
The difference between five 3s the first time and one 3 the second time
is your 12 .
I would say B but I can't see the question very well.