We are given the following phrases and their meanings in the code language:
1. 'nik mik sik' = 'I am beautiful'
2. 'mik rik' = 'beautiful painting'
3. 'rik sik tik' = 'I love painting'
Step 1: Identify words for 'beautiful' and 'love'
- From the first phrase, 'nik mik sik' means 'I am beautiful'. The word for 'beautiful' is \( \text{mik} \).
- From the third phrase, 'rik sik tik' means 'I love painting'.
The word for 'love' is \( \text{tik} \).
Step 2: Form the correct phrase
To write 'beautiful love', we need to combine the code words for 'beautiful' and 'love', which are \( \boxed{\text{mik tik}} \).
Thus, the correct answer is (3) mik tik.