Why does the woman say the "dinner" question is tough?

W: Ladies and gentlemen, I am Sue, your tour guide today. It’s my pleasure accompanying you today. If you have any questions while we’re going along, please don’t hesitate to ask.
M: I have a question actually.
W: Sure, what’s that?
M: Where’s the best place to have dinner around here?
W: (8)Well, that’s a tough question. There are so many good restaurants. My personal favorite is Spaghetti Alley.
M: How do we get there?
W: I’ll point it out when we pass it. It’s going to come up on your right in a few minutes.
M: (8)My daughter wants to know if we’re going to be passing any castles today.
W: Castles. No I’m afraid all of the castles are further into the city. We’re going to be staying near the coast today. I can give you a map of the city, though. It shows where all of the castles are.
M: Sorry, I have another question.
W: No problem. That’s what I’m here for.
M: (9)Are we allowed to take pictures once we get inside the museum?
W: Oh, I’m glad you asked that. I forgot to mention that taking photographs inside the art gallery and the museum is prohibited. However, you can take pictures of the grounds and the outside of the buildings. The architecture is beautiful.
M: Oh, and what time will we be stopping for lunch?
W: We’ll break around noon and meet back at the bus at 12:45 sharp.
M: I see. (10) Thank you for your detailed information.
W: You’re welcome.