Final answer:
Option D 'Before I do anything, I'm going to visit my mother' is a complex sentence.
Step-by-step explanation:
A complex sentence is a sentence that contains an independent clause and at least one dependent clause. An independent clause is a complete sentence that can stand alone, while a dependent clause is a sentence fragment that relies on the independent clause for its meaning. In the given options, option D 'Before I do anything, I'm going to visit my mother' is a complex sentence because it contains both an independent clause 'I'm going to visit my mother' and a dependent clause 'Before I do anything'.
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