Given below is a question followed by two statements numbered I and II, each containing some information. Decide which of the statement(s) is/are sufficient to answer the question.
Q: In a certain code language, ‘they are honest’ is written as ‘ra de si’.
What is the code for ‘are’?
Statement I:
In the same code language, ‘you are lucky’ is written as ‘si na to’.
Statement II:
In the same code language, ‘roses are red’ is written as ‘mo si lu’.

Correct option is C

Given:
In a certain code language,
“they are honest” → ra de si
So, one of ra / de / si means “are”.
Question:
What is the code for “are”?
Statement I:
“you are lucky” → si na to
Logic: 
The common word between the two sentences is “are”.
The common code between (ra de si) and (si na to) is si.
Explanation:
So, are → si.
Statement I alone is sufficient.
Statement II:
“roses are red” → mo si lu
Logic:
Again, the common word is “are”.
The common code between (ra de si) and (mo si lu) is si.
Explanation:
So, are → si.
Statement II alone is also sufficient.
Conclusion:
Either Statement I or Statement II alone is sufficient to answer the question.
Thus, correct option is (C).