This question concerns the use of conocer v. saber, both infinitives meaning "to know."
The difference: Saber is used to speak about known facts, while conocer is used to speak of familiar things.
Examples
Saber
I know where it is.
Yo sé donde está.
Conocer
She knows him.
Ella lo conoce.
The sentence in question
Tengo mucha hambre. ¿________ usted un buen restaurante italiano?
Translation:
I am very hungry. Do you [blank] a good Italian restaurant?
The person is asking if someone knows - or if they are familiar with - a good Italian restaurant. We know we will be using a conjugation of conocer, and not saber. That leaves two options: conoces and conoce. The correct conjugation depends on the subject. Our subject is usted, the formal "you" in Spanish. The correct conjugation is conoce, as conoces is the conjugation for the informal "you" (tú conoces).
Answer:
d) conoce