The correct option is D 1,2 and 3
Factors responsible for the rise of Heterodox sects:
1. The religion had turned complex, costly and rigid with rituals and ceremonies acquiring center-stage. So vedic rituals holded prominent place in the society at that time which became the reason behind the rise of heterodox sects.
2.The Bramhinical order had high degree of rigidity and new social groups like traders, merchants and craftsmen, having attained high economic status could not rise in social ladder.
3. Bramhinical religion was demanding the sacrifice of bulls and cows in rituals and ceremonies.
4. The religion had turned violent and the need for non-violent religion was responsible for emergence of heterodox sects.
6. The rapidly growing secondary economic activities demanded regular investment of resources.
All these factors were countered by new heterodox sects and their ideas were adopted by masses.