Graphic design as a distinct field can be traced back to the late 19th century, around the time of the Industrial Revolution. However, the principles and practices of visual communication date back much further, with origins in typography and printmaking.
If we consider the modern definition and practice of graphic design, it has been around for approximately 100 to 150 years. Therefore, the most appropriate choice from the options you provided would be:
A. 100 years
However, if we're considering the broader history of visual communication, which includes elements of graphic design found in various forms (like posters, advertisements, and typography), it could be argued that graphic design concepts have existed for up to 175 years or so.
Therefore, depending on how strictly one defines the term "graphic design," the answer could arguably be:
A. 100 years or B. 175 years.
Nonetheless, if we're strictly talking about established practices and the term "graphic design," A. 100 years is a more accurate selection.