Correct option is C
Given - CURD' is written as '342184' and 'BREAD' is written as '2181024'

Logic = the code number of vowel is the double of the place values of respective letter.

So, BUTTER can be written as
B - Code place values = 2
U - Code double of place values = 42
T - Code place values = 20
T- Code place values = 20
E- Code double of place values = 10
R - Code place values = 18
the answer is = 24220201018.
Option c is correct.