Answer:
2. Compound sentence: A woman holds an apple, and another smells a mango.
4. Complex sentence: When Laura answered the phone during lunch, Martha got upset.
Step-by-step explanation:
A compound sentence has two independent clauses, meaning simple sentences that can stand alone, as they both have a subject and a verb and express a complete idea. There´s a conjunction, such as "and" in this example, that joins both clauses together.
A complex sentence has an independent clause joined through a subordinator or relative pronoun to at least one dependent clause. A dependant clause is a sentence without either a subject or a verb, or that has both a subject and a verb, but it doesn´t express a complete idea. - A complex sentence always has a subordinator (as, because, since, after, although, when) or relative pronouns (who, that, which).