In a certain code language, ‘RICE’ is coded as ‘7613’ and ‘FIRE’ is coded as ‘1374’. Howis ‘C’ coded in the given language?

Given: 

In a certain code language, ‘RICE’ is coded as ‘7613’ and ‘FIRE’ is coded as ‘1374’. 

R, I, C and 1, 3, 7 are common in both.

So, the code of C is 6.