In a certain code language, ‘CARD’ is coded as ‘4681’ and ‘DOGS’ is coded as ‘3219’. What is the code for ‘D’ in the given code language?

Comparison Analysis
Word 1: CARD $\rightarrow$ Code: 4 6 8 1
Word 2: DOGS $\rightarrow$ Code: 3 2 1 9

Step-by-Step Logic
Identify the common letter: Looking at "CARD" and "DOGS", the only letter appearing in both words is 'D'.
Identify the common number: Looking at the codes "4681" and "3219", the only digit appearing in both sequences is '1'.
Conclusion: Since 'D' is the only common letter and '1' is the only common digit, 'D' must be represented by '1'.
The code for 'D' is 1.