Step-by-step explanation:
ΔG = free Gibbs energy change
If a reaction is endothermic (gains heat), ΔH is positive, and entropy decreases, ΔS is negative. Then, ΔG must be positive.
So, ΔG (+) if ΔH (+) and ΔS (-)
Answer: OA. When ΔH is positive and ΔS is negative