b.subordinate clause.
A subordinate clause is essentially a sentence fragment. It can't stand by itself and make sense. That means it is dependent on an independent clause for meaning. It can be connected to that independent clause either before or after it.
Ex.
Dependent (subordinate) clause: when you get home
Independent clause: We will watch TV.
Combined: We will watch TV when you get home.
Combined: When you get home, we will watch TV.
