A - Although he denies them, Dr. Vasequez faced several scandals last year.
A complex sentences must have both a dependent clasuse (although he denies them) and an independent clause (Dr. Vasquez faced several scandals last year.
Options B and D are compound sentences (two independent clauses) and option C is a simple sentence.
I can help I’ll be glad too...
<span>The best opening sentence for such a business/informal letter is B. Your order of February 10 arrived in our office today. This is the only sentence that doesn't sound too formal and use a bunch of fancy words in order to make it seem more formal, which is the reason why it is the least formal, in this case and thus the correct answer.</span>
<span>the answer to your question is gonna be to illustrate Jim's superstitious beliefs.
hope this helps :)</span>