If MP ₐ / Pₐ = MP B / Pᵦ

If MP ₐ / Pₐ = MP b / Pᵦ and MRP a / Pₐ = MRP b / Pᵦ > 1, this firm is

A) producing its output with the least costly combination of resources but is not producing the profit-maximizing output.
B) maximizing profits but failing to minimize costs.
C) neither maximizing profits nor minimizing costs.
D) combining resources a and b so as to minimize costs and maximize profits.