If firms in an industry are making negative economic profit in the short run, what does this mean?

a.Firms are making negative accounting profit and they will switch industries in the long run

b.Firms are making less accounting profit than their next best opportunity and they will switch industries in the long run

c.Firms are making negative accounting profit and other firms will enter into their industry in the long run

d.Firms are making lessaccounting profit than their next best opportunity and otherfirms will enter into their industry in the long run