The correct option is A Imperative Sentence
Sentences are mainly divided into four types: declarative, imperative, interrogative and exclamatory. Declarative sentences merely declare or state something, imperative sentences express a command, an order or a request, interrogative sentences intend to ask a question and exclamatory sentences display extreme or sudden emotion. The given sentence expresses a command, which means it's an imperative sentence. Even though it ends with an exclamation mark, it does not express any emotion; imperative sentences can also end with exclamation marks. Hence option A is correct and D is incorrect. It does not declare anything, or ask a question, hence options B and C are also incorrect.