How do we punctuate a subordinating adverb phrase or clause that comes before the main clause? no punctuation comma after the subordinating adverb phrase or clause comma after the main clause comma before the subordinating adverb phrase or clause

An Advervb Clause is a group of words that functions as an Adverb in a sentence. The Clauses can modify other words in the sentence, such as adjectives, verbs or adverbs. In general they add some information about the words or about the conditions of an action. The Adverb Clauses are flexible and can be placed at the beginning, middle or end of a sentence. So, a subordinating adverb phrase that comes before the main clause is followed by a comma.

B). Comma after the subordinating adverb phrase or clause.