Usually dogs are not referred to as persons, and neither married nor "unmarried". Also, persons who are (currently) divorced or widowed are certainly (currently) not married, but are often not called "unmarried" either; the latter word is often considered to mean "not currently married and never before".

In other words: if Anne is not a person, or currently not married but divorced or widowed, no married person (in that setting) will be looking at an unmarried person. Thus, the correct answer is "cannot be determined". It could be determined if you additionally knew that all three are persons, and that the word "unmarried" is used in the meaning "not currently married".

Scientists, New or old, can become bloody fools when they condescend to use the language of non-scientists.