Question

If the consumer's optimal bundle is a corner solution where all income is spent on good Y:
A. the indifference curve is steeper than the budget constraint at the optimal bundle.
B. the marginal rate of substitution is equal to the ratio of prices at the optimal bundle.
C. the indifference curve is tangent to the budget constraint at the optimal bundle.
D. The marginal rate of substitution is less than the ratio of prices at the optimal bundle.