Answer:
The complex sentence
Explanation:
The complex sentence is the best fit to this question; this is so because the complex sentence contains at least one dependent clauses and exactly one dependent clause.
In simple terms, the independent clause can be a sentence on its own while a dependent clause cannot. The two sentences are joined together by the use of a conjunction to make the sentence, grammatically right.
An example is
Although he was wealthy, he was still unhappy
