Who was declared as Person of the Year by  Time Magazine in 2019?
Greta Thunberg, Swedish environmental activist who is known for challenging world leaders to take immediate action for climate change mitigation.
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.
### Instruction: Who was declared as Person of the Year by  Time Magazine in 2019?
### Input: 
### Response: Greta Thunberg, Swedish environmental activist who is known for challenging world leaders to take immediate action for climate change mitigation.