Questões de Concurso Público Prefeitura de Cordilheira Alta - SC 2019 para Professor - Inglês

Consider the following statements:

I. ‘colder’ (line 09) is the superlative form of ‘cold’.

II. In line 11, ‘less sad’ is incorrect, ‘saddest’ should have been used.

III. ‘sadder’ (line 13) has a spelling error as it should have been spelled with only one letter ‘d’.

Which ones are correct?