Which word best completes the sentence to mean 'curious'?

For example, the sentence "Ich bin sehr neugierig auf das neue Buch."

In this context, 'neugierig' is a German adjective that translates to 'curious' in English. It is used here in its basic form to describe a state or feeling, which does not change regardless of the subject's gender, number, or case. The other options 'neugieriges', 'neugierige', and 'neugiertig' do not fit grammatically in this sentence.