Answer:
12
Step-by-step explanation:
Here's how to find the number of unique codes:
Possible first characters: There are four possible first characters (5, 6, 7, and 8).
Possible second characters: There are three possible second characters (c, d, and e).
Total unique codes: Since each first character can be combined with any of the second characters, and the selection of one character doesn't influence the other, we can multiply the number of possibilities for each character.
Number of unique codes = Number of possibilities (first character) * Number of possibilities (second character)
There are 4 possibilities for the first character and 3 possibilities for the second character.
Therefore, the total number of unique codes possible is 4 * 3 = 12.