Answer:
L23
L29
U23
U29
Step-by-step explanation:
We have two elements for the code:
Letter: The options are L and U.
Number: A prime number between 20 and 30, the options here are:
23, 29 (These are the only two prime numbers between 20 and 30)
Then the possible combinations are:
L23
L29
U23
U29