Which detail best supports the idea that the people in the future are confused about where the narrator has come from?

adapted from The Time Machine
by H.G. Wells

As they made no effort to communicate with me, but simply stood round me smiling and speaking in soft cooing notes to each other, I began the conversation by pointing to the Time Machine and to myself. Then, hesitating for a moment how to express Time, I pointed to the sun and at once a quaintly pretty little figure in chequered purple and white followed my gesture, and then astonished me by imitating the sound of thunder.
For a moment I was staggered, though the import of his gesture was plain enough. The question had come into my mind abruptly: were these creatures fools? You may hardly understand how it took me. You see, I had always anticipated that the people of the year Eight Hundred and Two Thousand odd would be incredibly in front of us in knowledge, art, everything. Then one of them suddenly asked me a question that showed him to be on the intellectual level of one of our five-year-old children—asked me, in fact, if I had come from the sun in a thunderstorm! It let loose the judgment I had suspended upon their clothes, their frail light limbs, and fragile features. A flow of disappointment rushed across my mind and for a moment I felt that I had built the Time Machine in vain.