You may not select a monster that can only be Special Summoned by a specific effect for this card’s effect, such as a Ritual Monster, “Chaos Emperor Dragon – Envoy of the End” or “Spirit of the Pharaoh”. If the only Monster Card in your hand is a monster such as these, then you cannot activate “Chosen One”.
If you activate “Chosen One” and your opponent chains “Lightforce Sword” to remove 1 of the 3 chosen cards from your hand, the effect of “Chosen One” cannot resolve and disappears.
Netrep Rulings:
Toon Monsters may be Special Summoned by the effect of “Chosen One” if “Toon World” is face up on the field.