Final answer:
Without the specific poem text, it's challenging to analyze the speaker's tone. However, Sumerian belief about the afterlife is known to be gloomy. Full context is necessary for an accurate literary tone determination.
Step-by-step explanation:
To determine the speaker's tone in the conclusion of a poem, it is important to consider the specific word choice and general atmosphere created by the text. Without having the actual poem with the phrase "Time capsule found on the dead planet," it is challenging to provide an accurate answer to the multiple-choice question. However, regarding the other question, Sumerian belief systems described the afterlife as gloomy. Answers to literature questions such as these also involve subjective interpretation, and often context from the whole poem or text is necessary to make an informed analysis.