A statement which cannot be understood

The correct answer is D. Incomprehensible.

A statement which cannot be understood is incomprehensible. This means that the statement is too difficult to understand, either because it is too complex or because it is written in a way that is not clear.

The other options are incorrect because they do not mean “cannot be understood.”

• Infallible means “never wrong.”
• Illegible means “cannot be read.”
• Inexplicable means “cannot be explained.”