Answer: He must resign, or face a painful, public dismissal.
Explanation: This sentence is a compound sentence because it has two independent clauses. When creating compound sentences, there are two punctuation rules to keep in mind: 1 Place a comma before the coordinating conjunction. 2 If you're not using a coordinating conjunction, place a semicolon between the clauses. As always, you use a lowercase letter to start the second independent clause.