History of Toothpaste

Today, people know how to take care of their teeth. Long ago, people's teeth would hurt and rot away as people got older. If someone had tooth pain, then the tooth got pulled out. Finally, people realized that they needed to clean their teeth. They just did not know the right tools to use. There was no toothpaste. So, people used lemon juice, ashes, or ground-up chalk. Sometimes, people would even clean their teeth with a mix of plants and honey. About 100 years ago, someone made a minty cream to clean teeth.
After a minty cream for teeth was introduced, the toothpaste tube was made to hold it. This allowed people to squeeze the paste onto their toothbrushes. During World War II, the army gave all the soldiers a toothbrush. At this time, tubes of toothpaste were made with metal. Today, they are made of soft plastic. This makes them much easier to squeeze. Now, shoppers can find many different kinds of toothpastes. People can choose different flavors and colors. There are even different types of toothpaste tubes.
1
Which of the following supports the central idea of the second paragraph?
A.
Today, there are so many different kinds of toothpastes people can buy.
B.
The toothpaste tube made it easier to get the toothpaste out.
C.
Toothpaste did not always have a minty flavor to it.
D.
People learned that cleaning their teeth was very important.