What color is the best?
These all three color are best in different different manners. Its depend on our self how and where using these colors. As an example If we are looking the dress for wedding dress then red and purple are best color specially for the women clothing but for the causal dress blue is always the best color.
That of course depends on your opinion and facial features. You may look nice in a bleach blond hair color but better in a dark or strawberry blond hair color. YOU may even look "the best" in a black hair color or even a red hair color. So, yes blond CAN be the best hair color depending how it looks on you.
I am a hairstylist that specializes in haircolor. My best opinion is to go to a professional. To color gray hair you need the 3 primary colors that are missing to "fill" the hair (the remaining color in gray hair is missing you need to put those back in- if you don't you get color that fades, color that isn't true, etc) A warmer natural based color will do best.