The scale factor is determined by dividing the length of the corresponding sides of the travel version triangle by the original triangle.
For the travel version of the piece, the length of each side is 0.5 inches.
For the original triangle, the length of each side is 3 inches.
Therefore, the scale factor is:
0.5 inches / 3 inches = 1/6
So, the correct answer is A. 1/6.