Consider the following arrangement that has some missing letters:
abab_b_bcb_dcdcded_d
The missing letters which complete the arrangement are:

The correct option is a, c, c, e.

Let us analyze the given letter sequence with missing places:
abab_b_bcb_dcdcded_d

There are 19 characters in total, including 4 missing letter spaces. Let us split the sequence into distinct repeated letter patterns or segments.

If we insert the letters a, c, c, e into the blanks in order:

1. First missing letter (at position 5): a
2. Second missing letter (at position 7): c
3. Third missing letter (at position 11): c
4. Fourth missing letter (at position 18): e

Substituting these letters into the sequence gives:
ababa | bcbcb | cdcdc | deded

We can clearly see a repeating pattern of 5-letter blocks, where each block alternates between two consecutive letters of the alphabet:
- Block 1: ababa (alternating 'a' and 'b')
- Block 2: bcbcb (alternating 'b' and 'c')
- Block 3: cdcdc (alternating 'c' and 'd')
- Block 4: deded (alternating 'd' and 'e')

Thus, the letters that complete the sequence logically are a, c, c, e.