Read the following article and select the best answer. Article: Perhaps the most famous clothing brand name in the world is Levi's.Levi Strauss & Co.is the producer of blue denim jeans.Here's how it happened. In the mid 1800s many people went to California to look for gold.A young German named Levi Strauss traveled to San Francisco to help his brother on business.He sold canvas to the workers for tents.But the workers said they needed pants more,because their pants were easy to wear out.Instead of selling his canvas for tent-making,he turned it into pants.These kinds of pants were very popular with workers.He was very happy and named the kind of pants"denims".And in 1853 he founded Levi Strauss & Co. Twenty years later the company began using a design with pockets.During the working,Strauss _ the process for putting metal rivets in the eans for strength. On May 20,1873,they received the U.S.Patent No.139,121 for the process and that date is now considered the official birthday of"blue jeans". Today the company still has its factories in San Francisco,California.Over 11,000 people work in them and bring in over $4 billion a year. Question: The passage mainly tells us _ . - who invented jeans - how jeans were invented - when jeans were invented - why jeans are so popular
A:
how jeans were invented