To solve this problem, the user needs to know the formula to calculate the perimeter of a square and the total number of poles required to build a fence.

The formula to calculate the perimeter of a square is P = 4s where P represents the perimeter and s represents the length of one side of the square.

To build a fence around a square-shaped region, we need two poles per unit of length. Therefore, the total number of poles required is twice the perimeter of the square.

Let s be the length of one side of the square. From the question, we know that the farmer used 27 fence poles on each side of the square. Therefore,

$2s + 1 = 27$

Solving for s, we get

$s = 13$

Substituting s in the formula for the perimeter of a square, we get

$P = 4s = 4\times13=52$

Therefore, the total number of poles required is

$2P=2\times52=104$

Hence, the answer is:

The Answer is: D. 104