A bag contains two red beads and two green beads. You reach into the bag and pull out a bead, replacing it with a red bead regardless of the color you pulled out. What is the probability that all beads in the bag are red after three such replacements?
Answer Choices
A. \dfrac{1}{8}
B. \dfrac{5}{32}
C. \dfrac{9}{32}
D. \dfrac{3}{8}
E. \dfrac{7}{16}