He must not attempt to escape or he will be put to death.
This is a ________ sentence.

The correct answer is Option C (Compound).

Key Points:
• English sentences are classified based on their structure into Simple, Compound, and Complex.
• Analyzing the sentence: "He must not attempt to escape or he will be put to death."
• It contains two independent clauses: 'He must not attempt to escape' and 'he will be put to death'.
• These two equal, independent clauses are joined by the coordinating conjunction 'or'.
• Definitions:
• Simple: One independent clause.
• Complex: One independent clause + one or more dependent clauses.
• Compound: Two or more independent clauses joined by coordinating conjunctions (FANBOYS: for, and, nor, but, or, yet, so).
• Therefore, this is a compound sentence. Option 3 is correct.
• Key Takeaway: A sentence with two independent clauses joined by coordinating conjunctions like 'or' is a compound sentence.