阅读下面短文,从下面每小题的A、B、C、D四个选项中选出最佳选项。
A frog was swimming in a pond after a rainstorm. He saw a brilliant rainbow across the sky. He was so excited that he couldn't help crying.
"I have heard there is a cave filled with gold at the place where the rainbow ends. I will find the cave and be the richest frog in the world," said the frog.
The frog swam to the edge of the pond as fast as he could. There he met another frog by accident.
"Where are you rushing to?" asked the second frog.
"I am rushing to the place where the rainbow ends," said the first frog.
"There is a saying that there is a cave filled with gold and diamonds at that place," said the second frog.
"Then come with me." said the first frog. "We will be the two richest frogs in the world."
The two frogs jumped out of the pond and ran through the grassland. There they met another frog.
"What's the hurry?" asked the third frog.
"We are running to the place where the rainbow ends," said the two frogs.
"I have been told there is a cave filled with gold, diamonds and pearls at that place," said the third frog.
"Then come with us," said the two frogs. "We will be the three richest frogs in the world."
The three frogs ran for miles. Finally they came to the end of the rainbow.
There they saw a dark cave on the side of a hill.
"Gold! Diamonds! Pearls!" cried the frogs. As they jumped into the cave, they found a snake lived inside.
He was hungry and had been thinking about his dinner. He swallowed the three frogs quickly.