select a counterexample for the given invalid argument.
-1. (∃x)(Mx • Nx)
2) (∀x)(Ox ⊃ Mx) / (∀x)(Ox ⊃ Nx)
A) Counterexample in a domain of 2 members, in which:
Ma: True Na: True Oa: False
Mb: True Nb: True Ob: True
B) Counterexample in a domain of 2 members, in which:
Ma: True Na: False Oa: True
Mb: True Nb: True Ob: True
C) Counterexample in a domain of 2 members, in which:
Ma: True Na: False Oa: False
Mb: True Nb: False Ob: True
D) Counterexample in a domain of 2 members, in which:
Ma: True Na: False Oa: False
Mb: False Nb: True Ob: True
E) Counterexample in a domain of 2 members, in which:
Ma: False Na: False Oa: False
Mb: True Nb: True Ob: False

Question

Quizplus · Accepted Answer

The argument is invalid because it assumes that if something is M then it is N, and if everything that is O is M, then everything that is O must be N. However, choice B shows a situation where something (a) is O and M but not N, which contradicts the conclusion that everything that is O must be N, thus serving as a counterexample.

Select a Counterexample for the Given Invalid Argument