The concept of indifference curve is based on the law of _______.

Correct option is C

The correct answer is (c) diminishing marginal rate of substitution.

• Indifference Curve: An indifference curve represents combinations of two goods that provide a consumer with the same level of satisfaction or utility.
• Marginal Rate of Substitution (MRS):This refers to the rate at which a consumer is willing to trade one good for another while maintaining the same level of satisfaction.  
• Diminishing MRS: The concept of diminishing MRS states that as a consumer consumes more of one good, they are willing to give up less and less of the other good to obtain an additional unit of the first good. This is because as they consume more of one good, its marginal utility decreases.