If the statement 'Some animals are birds', is given as false, then which of the following statements could be immediately inferred to be true?

A. All animals are birds.

B. No animals are birds.

C. Some animals are not birds.

D. All birds are animals.

Choose the most appropriate answer from the options given below:

The correct answer is B and C only.
Key PointsThe reasoning is as follows:

B. No animals are birds:

• This statement would be true if 'Some animals are birds' is false. If there are no animals that are birds, then it couldn't be possible for 'some' to be birds.

C. Some animals are not birds:

• This would also be true if 'Some animals are birds' is false. If there are not 'some' animals that are birds, it implies that at least 'some' animals must not be birds.

Statements A and D cannot be immediately inferred from the given statement being false.

Statement A, "All animals are birds", is clearly not true if "Some animals are birds" is false.

Statement D, "All birds are animals", does not have its truth-value affected by the original statement's truth-value, as it is about birds being animals, not about animals being birds.