The least possible Venn diagram for the given statements is as follow :
Conclusions :
I. All fishes are swimmers → False (There is no relation between fishes and swimmers given in the statements)
II. No fish is swimmer → False (There is no direct relation given between fish and swimmer. So, this statement is not definite)
III. Some fishes are swimmers → False (There is no direct relation given between fish and swimmer. So, this statement is not definite)
Also, Conclusion (2) and conclusion (3) form
complementary pairs.
So, this is an
Either or case.
Hence, the correct answer is
"Either conclusion II or III follows".