The Blue Grotto, or Grotta Azzurra, is a noted sea cave on the coast of the
island of Capri, Italy. It was discovered by a German writer in August 1826.
Since then it has become a popular tourist attraction. It is said that Roman
emperors used the grotto as a private bath and antique statues were found in
there. Inside the grotto, the sea seems to be lit from underwater. The
brilliant blue of the sea fascinates its visitors. The enchantment results
from another opening to the grotto, completely submerged. It allows the
sunlight to pass through and light the water from below, creating a blue
reflection that illuminates the cave. To get to Grotta Azzurra, there are
motorboats that leave from the port of Marina Grande. At the entrance to the
cave, passengers get into little rowing boats. The roof of the entrance is
only one meter above the sea level so passengers have to lie down in the boat
while passing into the cave. The grotto cannot be visited during adverse
weather conditions.
蓝洞，或者Grotta Azzurra，在意大利Capri岛的海岸著名海穴。在1826年八月由德国作
家发现。从那时起已成为一个热门的旅游景点。据说罗马帝国皇帝使用洞穴作为一个私
人浴室和古董雕像被发现在那里。里面的洞穴，海水似乎是从水下点燃。绚丽的蓝色大海
吸引著游客。另一个开放的石窟也令人着迷，完全淹没。它允许阳光通过，并点燃水从下
面，产生一个蓝色的反射照亮了山洞。走进Grotta Azzurra，也有摩托艇，从Marina
Grande的港口出发。在入口乘客划艇进入。入口处的屋顶只有离海拔一米以上，所以乘客
不得不躺下在船上当通过进山洞。石窟不能在恶劣天气条件下被参观。
Which of the following statements is true?
(A)Passengers take motorboats into the grotto.
(B)The grotto has become famous since the 18th century.
(C)There are two openings to the grotto.
(D)The grotto was open to the public in Roman times.
答案给C，请教今年底要考联招的高手们，A为何不能选？