Questões sobre Substantivos e compostos | Nouns and compounds

Considering the linguistic and semantic aspects of text CB2A2, judge the following item.   

The word “wonder”, in the first paragraph, is used here in the sense of “decide”.

Qual das palavras da frase, abaixo, é um substantivo?

He is in jail because of a criminal act.

Mark the alternative that presents the plural of the nouns below:

wolf – person – potato - brother

The plural form of “That kid is a good student” is “Those kids are goods students”. 

The plural form of “mouse” is “mice”.