Final answer:
The sentence contains a vague pronoun reference where the pronoun 'she' could refer to either Ms. Becker or her daughter, creating ambiguity.
Step-by-step explanation:
The question refers to a common issue in English writing called a vague pronoun reference. In the example sentence, 'Ms. Becker asked her daughter to chop the celery, but she couldn't find the knife', the pronoun 'she' is ambiguous. It is unclear whether 'she' refers to Ms. Becker or her daughter. This kind of ambiguity makes the text not adhere to clear use of pronouns as expected from conventional standards of clarity in writing.