Answer:
"I started inventing things, and then I couldn't stop, like beavers."
Step-by-step explanation:
Ambiguity can be defined as a stated that has more meaning than one.
The phrase that reflects the ambiguity in the excerpt is the first option that states "I started inventing things, and then I couldn't stop, like beavers."
The phrase is ambiguous because the narrator is trying to say that just like beavers never stop getting tired of chewing hardwoods because of new growing teeth, he is never tired of inventing things. When the narrator started inventing things he could not stop just like a beaver does not stop.
So, the correct option is the first one.