Which of the following would lead to the smallest entropy loss in the surroundings?

A. An exothermic reaction in a cold environment.

B. An endothermic reaction in a hot environment.

C. An endothermic reaction in a cold environment.

D. An exothermic reaction in a hot environment

B) An endothermic reaction in a hot environment.

Explanation:

Change in entropy = Change in thermal energy / Temperature in Kelwin

For loss of entropy, change in the thermal energy must be negative. It is possible only in case of endothermic reaction because it absorbs heat energy from the surroundings. Secondly the higher the temperature of surrounding, the lower will be change in entropy, because it is in the denominator of the fraction mentioned above.

Option B satisfies all the condition as mentioned above.