Two statements are given, followed by two conclusions numbered I and II. Assuming the statements to be true, even if they seem to be at variance with commonly known facts, decide which of the conclusions logically follow(s) from the statements.
Statements:
No headphone is an adapter.
All mobiles are adapters.

Conclusions:
I. No adapter is a headphone.
II. No mobile is a headphone.

Let's evaluate using Venn diagrams or set relations:
No headphone is an adapter means the set of Headphones and the set of Adapters are completely disjoint (no intersection).

All mobiles are adapters means the set of Mobiles is entirely contained inside the set of Adapters.

Now let's check the conclusions:

Conclusion I: No adapter is a headphone. Since no headphone is an adapter, the reverse statement is also perfectly true. Thus, Conclusion I follows.

Conclusion II: No mobile is a headphone. Since all mobiles are inside adapters, and no adapter can ever touch or overlap with a headphone, it is impossible for any mobile to be a headphone. Thus, Conclusion II follows.

Since both conclusions follow, the correct option is A.