Correct Answer: dur

Solution : Given:
1. dee duc tic ⇒ roses are red
2. bil doe ⇒ yellow carnations
3. tic dur doe ⇒ carnations are pink

By comparing all the coded sentences, we find that –
In sentences 1 and 3, are is a common word and tic is a common code.
In sentences 2 and 3, carnations is a common word and doe is a common code.
The remaining word and code in sentence 2 are yellow and bil sentence 3 are pink and dur.
Finally, are ⇒ tic ; carnations ⇒ doe ; yellow ⇒ bil ; pink ⇒ dur

So, pink will be coded as dur . Hence, the third option is correct.