My opinion is the answers A and D. I would choose A if you can only choose one, though.
Answer: A #3f107f.
Letter B would produce a lighter blue-purple color rather than a darker shade of purple. Letter C would produce a very light purple color. Letter D would produce a Black color, making it very dark and not in the range of being purple.
Letter A would produce a darker shade of purple. As explained in the way that the RGB color hexadecimal uses, the amount of each respective color is 2 digits for each color Red, Green, Blue respectively. By reducing the amount of each color in the RGB mode, the output will become a darker shade as the RGB mode is an ADDITITIVE type of color mode.
