Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series. b _ c e _ k b _ c _ f k b b _ e f _ b b c _ f k |
b, e, b, f, c, k, e b, f, b, e, c, k, e b, f, b, c, e, k, e b, f, b, e, c, e, k |
b, f, b, e, c, k, e |
b b c e f k / b b c e f k / b b c e f k / b b c e f k b, f, b, e, c, k, e |