Which of the following statements is true about a consumer's optimal decision when indifference curves are concave?

A) Both goods are consumed.
B) No goods are consumed.
C) Only one of the goods is consumed.
D) It occurs at the point of tangency with the budget line.

Indifference Curves

Graphical representations in economics that show different bundles of goods between which a consumer is indifferent, meaning that the consumer has no preference for one bundle over another.

Concave

A shape or curve that is curved inward, resembling the interior of a circle or sphere, often used in the context of economic functions.

Tangency

A point at which two lines or curves meet without intersecting, often used in economics to find points of optimization, such as in budget constraints or indifference curves.