Suppose that Betty's Beads is a typical firm operating in a perfectly competitive market. Currently Betty's MR = $13, MC = $13, ATC = $13, and AVC = $9. Based on this information, we can conclude that
a. Betty's is earning short-run economic profits that could be increased by reducing output and sales.
b. Betty's is suffering short-run economic losses that could be reduced by reducing output and sales.
c. Betty's is in long-run equilibrium.
d. Betty's is earning short-run economic profits that could be increased by expanding output and sales.