The new rules in the school's code of conduct -- including penalties for children hoarding candy and rewards for those sharing it -- have been criticized to encourage children to share opportunistically rather than altruistically.
A: hoarding candy and rewards for those sharing it -- has been criticized to encourage
B: who hoard candy and reward those who share -- have been criticized for encouraging
C: hoarding candy and rewarding them when they share -- have been criticized because of encouraging
D: hoarding candy, rewarding those who share it -- has been criticized for encouraging
E: who hoard candy and rewards for those who share it -- have been criticized on the grounds that they encourage
I choosed A. The explanation is confusing to me, at least as a non-native speaker it is almost impossible to get your official explanation. Furthermore, the explanation says that "has" does not fit because it is singular. But actually it IS plural in the original sentence. So where is the mistake?! This one makes me quiet confusing.