Under the law of equi-marginal utility, a consumer spending on goods X and Y is in equilibrium when:

1. The law of equi-marginal utility requires the marginal utility per rupee to be equal across goods. 2. This is the condition $\frac{MU_x}{P_x} = \frac{MU_y}{P_y}$. 3. Equating MUs or prices directly ignores the differing prices, and the product form is incorrect, so those options are wrong. _Source: ICAI BoS CA Foundation Paper 4 Business Economics, Ch 2 Unit II "Theory of Consumer Behaviour", p.7_