In each of the given questions, an inference is given in bold which is then followed by three-sentences(s). You have to find the sentence(s) from where it is inferred. Choose the option with the best possible outcome  as your choice

Fight tooth and nail.

I) The green party is fighting tooth and nail to save the world from the effects of climate change.

II) They fought tooth and nail to get the parental rights law changed.

III) I had to fight my way tooth and nail through the crowd to get to my seat at the concert.

IV) The family is going to fight tooth and nail to get justice for her son.