Which object would be the best addition to a collection of writing instruments that are unique to the twentieth century?

A. A pencil
B. A computer
C. A crayon
D. A calligraphy pen

D. A calligraphy pen

Since calligraphy pens are traditionally used for decorative writing and have been a popular tool for artists and writers throughout the twentieth century, it would likely be the best addition to a collection of unique writing instruments from that time period.