Final answer:
The Tropic of Cancer is the latitude 23.5 degrees north of the equator, where the Sun is directly overhead at noon on the summer solstice.
Step-by-step explanation:
The correct answer is that the Tropic of Cancer is a latitude where the Sun is directly overhead at noon on the summer solstice. Specifically, it is the latitude 23.5 degrees north of the equator. On the summer solstice, which occurs around June 21st, the Sun reaches its highest point in the sky at this line of latitude. If the Earth's tilt were less than its current 23.5 degrees, the Tropic of Cancer would be at a lower latitude, closer to the equator, leading to milder seasonal changes.