Answer:
The correct answer is: C. Saben.
¿Saben ustedes para qué sirve el documento?
Explanation:
First of all, as the subject of the sentence is USTEDES, the only possible options would be CONOCEN and SABEN.
However, the question here is: <u>"What is the difference between </u><u><em>saber</em></u><u> and </u><u><em>conocer</em></u><u>?"</u>
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We use <em>conocer</em> to confirm or deny the familiarity with a person, thing, place, etc.
<em>¿Conoces a mi tía Marta?</em> (meaning "Have you met my aunt Marta?")
<em>¿Conoces esta canción? </em>(meaning "Have you heard?" or "Does it sound familiar?")
<em>Conozco muy bien este barrio. </em>(meaning "I am familiar with this neighborhood.")
On the other hand, we use <em>saber</em> to say that we KNOW something (a fact, information, skill, etc.). It normally means that we can explain something, repeat it, do it, etc.
<em>¿Sabes francés? </em>("Do you speak French?" meaning that it is something you can do)
<em>Sé contar en alemán. </em>(I can count in German.)
<em>Me sé está canción de memoria. </em>(I know this song by heart.)
So, in the example above, the question <em>¿Saben ustedes para qué sirve este documento? </em>means <em>Do you KNOW...?, </em>and it supposes that you would be able to explain it.
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