Answer:
b. subordination
Explanation:
Subordination is linking two clauses in a sentence so that one clause is subordinate to (or dependent on) another.
In subordination, a subordinate clause is attached to the main clause with the help of a subordinating conjunction.
There are many subordinating conjunctions. Because is one of them.
Parallelism in a sentence means using constructions that are grammatically similar or identical in structure. We see none of these similar/identical elements in the sentence.