What is the latitude that is furthest north or south of the equator that gets direct sunlight directly overhead it? a) 3.5
b) 13.5
c) 23.5
d) 33.5

The correct answer is "C".
The latitude 23.5 degree north receives the sun light directly overhead. This latitude is called tropic of cancer. 
Whereas for southern latitude of 23.5 degree, the sun light is again receives directly overhead and this latitude is called tropic of Capricorn.