[tex]\frac{6}{18}[/tex] (B.)
6 + 5 + 4 + 3 = 18
[tex]\frac{6}{18}[/tex] = probability of getting a green marble
[tex]\frac{5}{18}[/tex] = probability of getting a yellow marble
[tex]\frac{4}{18}[/tex] = probability of getting a red marble
[tex]\frac{3}{18}[/tex] = probability of getting a purple marble
Hope it helped,
BioTeacher101