According to Robert Justman, what was significant about George Takei's portrayal of Hikaru Sulu in the original Star Trek series?

A. He was the first Asian actor to play a villainous character
B. He was the first actor to play a character from a specific planet
C. He was the first actor to play a character with a disability
D. He was the first Asian actor to portray an Asian character in a positive light
Answer: 