My political opponent is proposing an exorbitant ‘sin tax’ on sugary drinks. Ladies and gentlemen, if we start to accept this kind of nannying interference in our dietary choice making, we’ll soon be submitting to being weighed by the police and made subject to financial penalties if found to have gained weight!”

The argument-type above, which posits an improbable and obviously undesirable outcome as the likely result of acceding to an opponent’s position, is called…
Select one:
a. An equivocation
b. A false dilemma
c. A slippery slope
d. An appeal to authority

The equivocation, false dilemma, slippery slope, and appeal to authority are all examples of fallacies often used by people during debates. The argument you were given is an example of a slippery slope - a logical fallacy in which a person claims that a relatively small first step will lead to a chain of events that will result in something significant and usually very negative. This is exactly what the person from the example is claiming - that the so-called sin tax will lead to the police weighting people and making them pay if they have gained weight.