Answer:
It's a complex sentence.
Step-by-step explanation
I searched up the definitions of the three first being the simple sentence simple sentences are just easy and you could look at it and just know right away whilst compound sentences are different. Compound sentences have independent clause ((if you don't know what that is I encourage you to search it)) if the independent clause has a comma before it then it will be a compound sentence but in this case its not that either so its the complex sentence. good luck hope this helps!!