What causes an indifference curve to be convex to the origin?

1. Marginal utility
2. Market Rate of Exchange
3. Law of Diminishing Marginal Rate of Substitution
4. Law of Increasing Marginal Rate of Substitution

Option 1 -> Marginal utility relates to satisfaction from consumption but doesn't directly determine indifference curve shape.

Option 2 -> Market Rate of Exchange relates to prices and budget constraints, not preference curves.

Option 3 -> Law of Diminishing Marginal Rate of Substitution explains why consumers give up less of one good for additional units of another as consumption increases.

Option 4 -> Law of Increasing Marginal Rate of Substitution would create concave curves, not convex ones.

Hence, Option 3: Law of Diminishing Marginal Rate of Substitution -> The Marginal Rate of Substitution (MRS) represents the rate at which a consumer is willing to substitute one good for another while maintaining the same utility level. As a consumer has more of Good X and less of Good Y, they become less willing to give up Good Y for additional units of Good X. This diminishing willingness to substitute creates the characteristic convex (bowed inward) shape of indifference curves. For example, if you have many pizzas but few burgers, you'd give up many pizzas for one burger; but if you have many burgers and few pizzas, you'd give up fewer burgers for one pizza. This diminishing MRS as you move along the curve creates the convexity -> correct