In a certain code language, '78623' is coded as 'TAKEN' and '32685' is coded as 'TOKEN'. What is the code for '5' in that language?

Given:
'78623' 'TAKEN'
'32685' 'TOKEN'

​Comparing both words T,K,E,N are common same as number 2,3,6,8 are common

So different is O,
So code of 5 is O. ​​​

Thus, the correct option is (c).