Already Heesub explained It's 리나 When you write your name in Korean, If your name don't have sounds like받침(final consonant) ex) 제이"슨" Ja"son", you don't need put together at same time.

리나 is correct for Lina. 린아 would be accepted as 린(the name) + 아(addressing suffix) like in "철수야"(철수 is name) or "수철아"(수철 is name)

I would assume 리나. 린아 is "Lin" spoken to in 반말.