Ok, after doing an immense amount of research I came up with the most logical answer.
A. Is indicated by a negative enthrall sign.
Reasoning: an endothermic reaction is ice melting and the energy being more than its surroundings. Not specified to ice but as an example, ice is endothermic. That puts d and b out of the running leaving you left with a and c.
When I searched up enthalpy, it said “When a substance changes at constant pressure, enthalpy tells how much heat and work was added or removed from the substance.” Which is similar to c, right? Yeah, meaning both a and c are similar in that aspect.
The reason I decided to go with a is because heat is NOT released into the surrounding, exothermic reactions release energy and heat into the surrounding.
