Which of the Following Conditions Is Not Necessary for the Attainment

Which of the following conditions is not necessary for the attainment of efficiency in general equilibrium?

A) The economy's marginal rate of transformation must be equal to each consumer's marginal rate of substitution.
B) Consumers must have identical incomes.
C) Marginal rates of technical substitution must be equal for all firms.
D) Marginal rates of substitution must be equal for all consumers.