When a sentence begins with a subordinate, or dependent, clause followed by the main, independent, clause, a comma is placed after the subordinate clause to separate it from the main clause. For example, Although it was raining, we went for a walk uses a comma right after the subordinate clause Although it was raining and before the main clause we went for a walk.
A dash is used for a sharper, more dramatic break and is not the standard mark for this structure. A semicolon joins two independent clauses of roughly equal weight, but a subordinate clause is not independent, so a semicolon does not fit here. A colon is used to introduce a list, explanation or quotation, not to separate a subordinate clause from a main clause.
Since the comma is the standard mark used when a subordinate clause comes before the main clause, option 3 is correct.