Considering the question and the words in it, the part of speech that cannot be classified in the question is "interjection."
This is because interjection is a word or phrase that is grammatically self-reliant from the words around it.
For example, interjection is "Oh, what a lovely week!"
An example of the verb in the question is "can."
An example of an adjective in the question is "solitary."
An example of the preposition in the question is " as."
Hence, in this case, it is concluded that the correct answer is option D. "interjection."
Learn more about interjection here: https://brainly.com/question/25037175
