I said 15 LOL . I think its C (you and nav. said it was A). Oswald process, i just talked about temp/pressure required for all of them.... related to equilibrium...then talked about activation energy, particicle colission theory and noted that VERY different exothermic conditions between the 1st and 2nd/3rd steps. (the 1st one was like -950...while 2nd and 3rd were about 110ish???) wbu?