Hello. You did not enter the text to which this question is related, which makes it impossible for it to be answered. However, I will try to help you in the best possible way.
It is only possible to answer this question by reading the text. However, it is important that you know that the tone of a text is the feeling that the author wants readers to feel when reading. Therefore, the text has words that express this feeling and signals to the reader what should be felt. For example, texts that have a happy tone, can present words like "joy," "happiness," "delight," "joy," among other words that express that feeling.
Following this reasoning, we can say that a declaration of emancipation can present a tone of firmness and seriousness. In this case, to answer this question you must read your text and identify words that convey this type of sensation.