"Excoriate" means to criticize someone or something severely and harshly, to denounce scathingly (it literally meant to strip off skin). This question asks for the word most opposite to this harsh criticism.
Since excoriate means to criticize severely, its true opposite is a strong word of praise, which is "Acclaim."
Let's summarize:
So the correct answer is "Acclaim."
If the price of a commodity increases by 25%, by what percentage should the consumption be reduced to keep the expenditure the same?