题目

阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。World's best scuba diving destinationsIf you areplanning to go on a scuba diving vacation in the near future, here is a list ofsome of the best destinations in the world that you can consider.The Red Sea, EgyptOne diveunderneath the surface of the Egyptian Red Sea, and all you can see is a hugevariety of marine life all around you. This is one of the richest marineecosystems in the world. You can experience a fantastic swim with the dolphinsand sharks. And a variety of colorful coral and sponges（海绵关于的方程是一元二次方程，则满足的条件是（   ） A．＞0            B．≠0            C．＝1            D．≥0