Answer:
The revelation made in this passage:
“Had I but died an hour before this chance, I had lived a blessed time; for, from this instant, There's nothing serious in mortality: All is but toys: renown and grace is dead;”
Is:
C. Macbeth's sadness and sense of loss at the act that he has committed.
Explanation:
This is said after Macbeth realizes the atrocity o his act. Then, he thinks about the effects of it and wishes he has had a chance to think about it because he understands that humans are mere puppets of bigger objectives and purposes and that there is a lot we can regret about because we can perform horrifying acts lead by reasons that are not as meaningful as we thought they were. And that the only ones safe from this are the dead.