题目选项分析

Since 1978 when the copyright law was changed, books that are less than fifty years old must not be photocopied without the publisher's permission. Thus, any book that has been photocopied since 1978 without the publisher's permission must be at least fifty years old.

The reasoning above exhibits a flaw similar to one in which of the following?

【选项】Anyone who rides a city bus must buy a bus pass, and since Demetrios has a bus pass, he must be riding on a city bus.