Correct Answer: la

Solution : Given:
1. se mi da ⇒ I have friends
2. la ki se ⇒ Friends are good
3. na de ki ⇒ She is good

By comparing all the above-coded sentences, we find that –
In sentences 1 and 2, friends and se are common.
In sentences 2 and 3, good and ki are common.
The remaining word and the code in sentence 1 are I/have and mi/da , in sentence 2 are are and la, in sentence 3 are She/is and na/de
Finally, friends ⇒ se; good ⇒ ki; are ⇒ la;  I/have ⇒ mi/da; She/is ⇒ na/de

So, are will be coded as la . Hence, the third option is correct.