Which of the following arranges the groups in order of decreasing priority according to the sequence rules?
a. CO₂H > CH₂OH > CH₂CH₃ > CH₃
b. CH₃ – CH₂CH₃ – CH₂OH > CO₂H
c. CH₃ > CH₂CH₃ > CO₂H >CH₂OH
d. CH₂OH > CO₂H > CH₂CH₃ > CH₃