We start by identifying a logical opener. Sentence C — "it would be less difficult to bear the evils of one’s own life if" — introduces a conditional clause and clearly needs to be followed by a reason.
Following C, sentence A — "there was the hope that in another existence a greater happiness would reward one" — completes the conditional idea, giving the reason why it would be easier to bear life’s evils.
Next, sentence B — "previous existence, and the effort to do better would be less difficult too when" — continues the thought by connecting the idea of a past life and motivation for improvement. The "previous existence" refers back to the errors mentioned later.
Finally, sentence D — "one could think that they were but the necessary outcome of one’s errors in a" — logically concludes by tying back to B’s mention of the previous existence, explaining that the hardships are consequences of past mistakes.
Thus, the full meaningful sentence is:
C → A → B → D, matching option (a) CABD.