What common tool is used to measure type size and leading in graphic design?

The correct choice for measuring type size and leading in graphic design is a pica ruler. A pica ruler is specifically designed for the printing and publishing industry and provides measurements in both picas and points, which are standard units used for typography. One pica equals 12 points, making it a crucial tool for designers who need to ensure the proper spacing and sizing of text within their designs.

While type gauges and E-scales also relate to typography, they are generally not as widely recognized or utilized as the pica ruler in professional graphic design settings. A measurement wheel is typically used for measuring distances on physical surfaces and is not relevant to the precise needs of typographic measurement. Therefore, the pica ruler remains the standard and preferred instrument for designers focusing on type size and leading adjustments.