Translation:Please pay attention to your health!
I believe they are all interchangeable. In English we may say, how is your health, are you taking care of your body, are you taking care of yourself. Just different ways to say the same thing. Maybe that is way they give us the variations. When they show the sentence in English and I put my finger on the word, health, it shows all 3 choices. I found that when having to put the chinese phrase together, i will check All of the choices. If it shows shenti and jiankang, i will choose them both, otherwise i may get it wrong. Just my experience. Sometimes i think they are looking for a particular response.
This is a perfect example of how hard it is to create an automated Chinese/English course. Unlike Romance languages, there is less correspondence with a literal translation between Chinese and English. There are probably 100 semantically correct translations. But I guess some day NLP will be in charge of the translations, and we'll all be laughing about the odd by grammatically correct answers it will accept.