In this problem:

Sally told Janice that she made the honor role.
__ Pronoun shift in number
__ Pronoun shift in person
__ Ambiguous reference
__ No error

What does ambiguous reference mean?

The ambiguous reference is that we don't know who made the honor roll -- Sally or Janice. To whom does "she" refer?

Ambiguous reference refers to a situation in which a word or phrase in a sentence can be interpreted in more than one way, making the meaning unclear or confusing. In the given options for the problem, "Ambiguous reference" suggests that there is a problem in the sentence that relates to the clarity of the reference to a specific noun or pronoun. It implies that there may be uncertainty or confusion about the identity of the pronoun or noun being referred to.