"Julia's uncle is sick."
Translation:जूलिया के मामा बीमार हैं।
I'm not sure why चाचा is wrong, or why it is an option along with मामा. Are they both not words for uncle? I see nothing in the sentence which tells us if it is a maternal or paternal uncle.
Any of मामा, चाचा, मौसा, and फूफा should be accepted. I hope you used the report button.