This sentence is asking a question, which makes it an interrogative sentence.
Here's a description of each type of sentence you listed:
Imperative: a command - this sentence will end with a "." (Pick the hat up.)
Exclamatory: excitement or enthusiasm - this sentence ends with a "!" (I'm so excited about going to Disney!)
Declarative: a statement - this sentence ends with a "." (I like tacos.)
Interrogative: asks a question - this sentence will end with a "?" (Whose pink hat is that on the floor?)
Hope this helps you!