Step-by-step explanation:
Lower class is defined as the class of society with poor economic value and so called low status in society.
Middle class is defined as the class of society with adequate economic condition and medium prestige in society.
Upper class is defined as the class having the sufficient amount of money and no necessities go worthless and useless.
But,in my view,I consider the people upper class who are rich in knowledge and have the sense of humanity.
Keep smiling and hope u are satisfied with my answer.Have a good day :)