No finished projects are uncompleted works. Therefore, no completed works are unfinished projects.
A) Valid; no fallacy.
B) Invalid; illicit contraposition.
C) Invalid; illicit contrary.
D) Invalid; illicit conversion.
E) Invalid; illicit obversion.

Question

Quizplus · Accepted Answer

The argument commits the fallacy of illicit contraposition. It incorrectly assumes that reversing and negating both terms of a categorical proposition (from "No finished projects are uncompleted works" to "No completed works are unfinished projects") preserves the proposition's validity, which is not logically sound in this context.

No Finished Projects Are Uncompleted Works