A consumer is said to be in equilibrium, if

In economics, consumer equilibrium is a state where a consumer derives maximum satisfaction or utility from their expenditure. It occurs when a consumer, given their fixed level of income and the prevailing market prices of goods, allocates their spending in a way that fulfills their needs and wants optimally.

Option A is correct because it describes the situation where a consumer manages to maximize their utility and satisfy their requirements within the constraints of their specific budget. It signifies a point of balance where the consumer has no incentive to change their consumption pattern unless their income or the prices of goods change. Options B, C, and D are incorrect as they either refer to subjective levels of luxury, arbitrary restriction of consumption, or the acquisition of more wealth, none of which define the technical state of equilibrium.