Brainliest for the correct answer!

Here is another persons answer I think it’ll be location 3 as well

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen

Why you put last one a? i think is b.