Which logical fallacy is used in the text?
Denise said there's no way Scotland's Loch Ness Monster is real, but she's not even Scottish, so there's no way she could really know.

 - slippery slope fallacy: the false assumption that a small first step will lead to extreme consequences
 - ad hominem: an attack against the person making the argument, rather than the argument itself
 - circular reasoning: an argument that supports a claim with the claim itself
The text argues that Denise's claim that the Loch Ness Monster isn't real is not valid because she's not Scottish. This is a personal attack on Denise's background that isn't relevant to whether her claim is valid. This illustrates a type of logical fallacy known as ad hominem.