Mark the letter A, B, C, or D to indicate the sentence that best combines each pair of sentences in the following questions   The president failed to explain the cause of the crisis. He did

The president failed to explain the cause of the crisis, nor did he offer any solutions

The president offered some solutions based on the explanation of the cause of the crisis

Not only did the president explain the cause of the crisis, he also offered solutions

Although the president explained the cause of the crisis, he failed to offer any solutions