The correct answer is Complex
Step-by-step explanation:
In grammar, sentences are classified as simple, compound, complex or compound-complex depending on the type of clauses that are part of them, in general terms clauses are independent if they express a complete thought and do not need from others or as dependent if they need from other sentences to be complete. In the case of complex sentences, these are sentences that contain a dependent clause joined to an independent clause usually by subordinating conjunction such as while, when, because or although.
This is the case of the sentence "Although it is not as wealthy as South Africa, Mozambique is the site of the second biggest port in all of Africa" in which there is a dependent clause "it is not as wealthy as South Africa" as this clause does not express a complete idea and an independent clause "Mozambique is the site of the second biggest port in all of Africa" and both are linked by the subordinating conjunction "Although". Therefore, the sentence presented can be classified as a complex sentence.