The answer would be C I believe.
Answer: To put it bluntly, “Thanatopsis” is about death. The word thanatopsis itself derives from the Greek roots thanatos death and opsis sight. In other words, the poem always has death in its sights. One of the speaker's main goals seems simply to make death and its inevitability vivid for the poem's readers.
Explanation:
The gerund in the sentence provided above is backpacking. Gerunds are verbs in -ing form but function as a noun. In this sentence, it functions as a direct object because it answers the question "what". By this, we can construct the question "What popular pastime is being talked about?".
