What appears to be one of the major problems with simultaneous lineups, but is less of a problem with sequential lineups?

a. The foil bias disappears in simultaneous lineups.
b. The chances of misidentifying the perpetrator's identical twin are increased.
c. The witness may focus on the person (i.e., "foil") who most closely resembles the perpetrator, if the perpetrator is not in the lineup.
d. The witness often misses the perpetrator because (s)he is told (s)he might not be in the lineup.