It contains one dependent and one independent clause.
Answer: Option 3.
Explanation:
A dependent clause is also known as the subordinate clause. It is that which is a part of the sentence which adds extra information to the particular sentence of which it is a part. But it is nothing without a sentence. It can not stand without it.
On the other hand, independent clause is a clause which has a meaning itself also. In other words, it stands as an independent sentence in itself and does not need to be a part of some other sentence necessarily to make a meaning out of it.
