You are Ron

"Listen, Lavender," you say, watching her eyes perk up at the softer tone of your voice. "What matters is finding that horcrux, and we need you."

That furious, convulsive expression on her face simmers down into a sly smile. "Well if I'm needed," she says, "count me in. What are we looking for exactly?"

"I believe it's Rowena Ravenclaw's diadem," Cho says, "based on what Hermione concluded." You detect a slight sneer out of Lavender, but she chooses to stay quiet.

"Did someone say diadem?" inquires an airy voice, hidden behind Cho. You know immediately it's Luna. "I know a lot about that diadem. I do think Voldemort would use it as a horcrux. Actually, my dad mentioned that in The Quibbler once, but it was in the same issue as the one about Cornelius Fudge secretly being a blast-ended skrewt. It kind of got buried."

"That's the most ridiculous thing I've ever heard," you mutter, referring to the Fudge accusation. "Really, that's barking mad!"

"My father had a highly reputable source," Luna responds calmly.

"Was it a nargle?" Cho asks.

"Nargles rarely talk, if at all" Luna answers matter-of-factly. "Actually it was a polar bear named Iorek, but I doubt any of you know him."

"‘Fraid not," you say dismissively. "Any other tips, Luna?"

"The diadem used to be at Hogwarts," she tells you, "but I doubt it's there anymore. Rowena was very protective of her things. I imagine she would have had it hidden far away. Beyond oceans even."

"Thanks, Luna," you say appreciatively.

She smiles and mutters, "I used to think wit beyond measure was man's greatest treasure, but now I think it's friendship. Good luck, Ron!"

Surprised by her affability, you turn back to the rest of the group and shrug. Maybe the best person to ask is Hagrid, your mentor. You thought you saw him hanging around the candy section.

"Hey Hagrid!" you yell. He smiles and comes barreling across the room.

"Well ‘ello there, Ron. Where are yer' headed?"

"We have to find something," you respond. You know that you can trust Hagrid, but you're still hesitant to spell out your whole mission. "There's this diadem out there. If we find it, we might be able to stop Voldemort."

"Blimey, Ron! This sounds like some serious business!" Hagrid roars. "Do you know what yer gettin' yerself into?"

You let out a sigh. "We have to do it, Hagrid. It's the only way we can keep everyone safe. Have you after heard about about a dodgy crown?"

"Can't say I ‘ave." Hagrid leans in a bit toward you. "But I'll tell ya what. You best start yer search in Knockturn Alley. There's loads of foul magic floatin' about round there."

"Thanks, Hagrid." You give him a kindhearted clap on his arm, which feels as broad as a small tree trunk, and walk back to Cho and Lavender.

Cho pipes up as soon as you return. "I know Luna doesn't think the diadem is at Hogwarts, but I just can't see it being anywhere else. All remains of the ancient Ravenclaw family remain within its walls. As far as I see it, that's where we need to start."

"Trying to just waltz into Hogwarts is awfully risky," Lavender points out.

"Well, we can foxtrot instead! Tango, perhaps!" Cho shoots back. "Either way, it's a risk we have to take!"

Should you:
A.) Go to Hogwarts?
B.) Go to Knockturn Alley?