What is Rotelle's point? That Sim's is too old to effectively address issues facing the country.
Answer choice (D) states: "If anyone can effectively address the difficult issues facing the country, that person must be younger than Sims."
Clearly, Rotelle is committed to the answer choice since he believes that Sims is too old. So, anyone older than Sims would be too old, as well. It's also important to note that we do not know exactly how young one must be, nor do we know that being young guarantees that one will effectively address the difficult issues facing the country. We merely know that Sims is too old to do so. Thus, one who could effectively address the issues must be younger than Sims, i.e. answer choice (D).
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