Balancear por tanteo las siguientes ecuaciones químicas 1. Mn2O7 --> MnO2 + O2
2. PbS + O2 --> On + SO
3. Fe(OH)3 + H2SO4 --> Fe2(SO)3 + H2O
4. P4 + Fe2 --> PF2
5. C + O2 --> CO2
Por favooor, alguien que me ayude rápido

Which one from below is not one of the reasons of planning failures? (clo3) a)-planner is careless. b-planner spend less time in the field but more time on the desk c)-planner is not qualified d)-planner does not have sufficient time to properly plan