Final answer:
Racism led to unequal treatment and harsh conditions for Chinese laborers while building the transcontinental railroad.
Step-by-step explanation:
Racism played a significant role in the challenges endured by Chinese laborers while building the transcontinental railroad. Option B) Racism led to unequal treatment and harsh conditions is the correct answer. Chinese laborers were often given the most difficult and dangerous jobs. They faced discrimination, lower pay, and segregated living quarters compared to other workers. Additionally, the Chinese Exclusion Act of 1882 barred Chinese immigrants explicitly based on their race, further perpetuating their mistreatment.