Read the sentences from Barrio Boy by Ernesto Galarza. Suspecting something, he added: "When you are finished, don't forget to pull the chain. See. That's what the sign says." And, to be sure, there was a paper with writing tacked to the wall, next to an aluminum up-and-down pipe.

The hotel clerk most likely suspects that Ernesto and his mother

do not notice the sign on the wall.
have to go to the bathroom right away.
do not understand what the sign says.
think flushing a toilet is a waste of water.

do not understand what the sign says.

Explanation:

"Barrio Boy" is an autobiography of Ernesto Galarza, which was published in 1971. He recounts his travel memories during the Mexican Revolution–of how his family traveled towards California due to the maltreatment of Mexicans in Mexico.

Upon trying to adapt to the American society, Ernesto and his mother discovered the indoor toilet in a hotel located in Nogales. The hotel clerk most likely suspected that Ernesto and his mother could not understand what the sign says because of their lack of knowledge on indoor toilets. The hotel clerk then gave them further instructions on what to do. Ernesto was fascinated by it that he even went several trips to the toilet before he was ordered to sleep.