When a Market Has Barriers to Entry

When a market has barriers to entry,

A) then in the long run it is possible for the firms to incur economic losses.
B) then in the long run the only possible outcome for the firms is zero economic profit.
C) then in the long run it might be possible for the firms to make economic profits.
D) oligopolies cannot be created.
E) the HHI almost always falls below 1,000.