Letter series type of questions usually consists of a series of small letters which follow a certain pattern. However, some letters are missing from the series. These missing letters are then given in a proper sequence as one of the alternatives. The candidate is requitred to choose this alternative as the answer.
a _ bccb _ ca _ cca _ baab _ c
The series is aabcc / bbcaa / ccabb / aabcc.
The letters move in a cyclic order and in each group, the first and third letters occur twice.