A. Neil
B. Amazon
C. Indus
D. Yangtze

Rank River Location Approximate Length—km
1. Nile Africa 6,650
2. Amazon South America 6,400
3. Yangtze China 6,300

The Nile is the longest river in the world, with a length of about 6,650 km, and the Amazon is the second longest, with a length of at least 6,400 km.

https://en.wikipedia.org/wiki/List_of_rivers_by_length