We want to see where Oliver is making a mistake in his claim.
The correct option is the first one, the simplification on the last step is wrong.
We start with the expression:

Now, by looking at Olvier's work, we can see that on the last step he writes:

This is clearly wrong, as the numerator and the denominator are dont simplify to -1 (this only happens if the numerator is -1 times the denominator), so the left side can't be equal to -1, it actually would be simplified to:

Then the correct option is the first option.
If you want to learn more, you can read:
brainly.com/question/14324500