Answer: C. 358,800,800
Explanation:
Total digitrs ( from 0 to 9 ) = 10
Total letter ( from a to z ) = 26
To make the code , we require 4 letters followed by 3 digits .
If letter can be used once ( i.e. repetition is not allowed) , then the number of ways to arrange this sequence of letters =
[By using Permutation]


But repetition is allowed for digits , so number of ways to arrnge 3 digits =

Now , the total number of ways tio make the code = 358800 x 1000
=358,800 ,000
Hence, the correct option is C. 358,800,800.