Final answer:
American miners were most angered by the success of Chinese miners in finding gold, which led to resentment and discrimination, culminating in the Chinese Exclusion Act of 1882. Option A is correct.
Step-by-step explanation:
The characteristic of the Chinese miners that most angered the American miners was A. Their success in finding gold. The Chinese immigrants were perceived as frugal and hardworking, often making profitable the mining sites abandoned by others. This industriousness led to resentment among American miners, who felt that the Chinese, comprising about 8 percent of the nearly 300,000 who arrived during the gold rush, were depriving them of their livelihood. The animosity towards the Chinese miners contributed to instances of discrimination, violence, the imposition of a special tax on Chinese miners, and eventually, the Chinese Exclusion Act of 1882.