Question

\marge is learning skills faster than all the other dogs in my training group,\ stefon told his uncle. \she can find eyeglasses and keys now. and just today, i showed her your dead phone, and she brought me the charger!\ uncle dwayne polished his glasses in silence for a while. \thats great, stefon,\ he said at last. \youve always had a way with animals. but remember, in a few more months, shes going to be finding someone elses charger.\ stefon focused on rubbing marges ears. uncle dwayne was right, of course. still, stefon didnt want to think about marge living with someone else. he didnt want to picture her opening doors and pushing crosswalk buttons for some stranger. some stranger who wasnt him. what is the most likely reason why uncle dwayne is quiet after stefon tells him what marge can do? he is mad at stefon for reminding him about the dead phone. he doesnt really believe that marge can do all these things. he is worried that it will be hard for stefon to give marge up. he thinks stefon is boasting too much about marges skills.

Explanation:

The text reveals Uncle Dwayne knows Marge will be placed with another person once her training is complete. His silence comes from recognizing how attached Stefon is to Marge, so he worries Stefon will struggle to give her up later. The other options don't align: he isn't mad about the phone, he acknowledges Marge's skills, and he doesn't accuse Stefon of boasting.

Answer:

He is worried that it will be hard for Stefon to give Marge up.