Question

What happened in the Albigensian Crusade from 1209 to 1229?
Crusaders tried to reconquer Jerusalem, which had fallen again into Muslim hands.
This crusade, known as the "Children's Crusade", resulted in many of the child Crusaders being sold into slavery.
Crusaders tried to conquer southern France, because many people there were considered heretics.
All of the answers are correct.

Answer 1

The best option from the list regarding the Albigensian Crusade from 1209 to 1229 would be that "Crusaders tried to conquer southern France, because many people there were considered heretics," since those being attacked had diverged from the teachings of the church. 

Answer 2

Crusaders tried to conquer southern France, because many people there were considered heretics happened in the Albigensian Crusade from 1209 to 1229.