Question: Two years ago, I met Agent GreatBooks at a literary conference, who was excited about my first couple of pages and wanted to see the ms when it was complete.
Now it's complete. After looking up Agent GreatBooks and her agency, on their website and on Publishers Marketplace, I think her agency is great. However, her colleague Agent LotsaWords is a better fit--she's sold more in my category and I like the look of her deals.
Option A: Query Agent GreatBooks only, the tenuous connection is better than a cold query.
Option B: Query Agent LotsaWords and name-drop Agent GreatBooks and our previous meeting.
Option C: Query Agent GreatBooks but mention that I might also be a fit for Agent LotsaWords (soooooo presumptuous, I am thinking).
Option D: Shark's Choice/Other
Help me, Obi-Shark Kenobi, you're my only hope!
You should query the agent who seems to be the best fit for your work regardless of previous meetings, contacts or introductions. Just because she met you first Agent GB has no claim on you, NOR do you owe her any kind of first right of refusal, or first look. This is business, not the Roland Park Ladies Tea.
Thus: Option B/sorta is the right choice. And by sorta I mean you don't mention Agent GB at all.
Exceptions to this are:
Agent GB has kept in touch with you during the last two years on her own initiative;
Agent GB read the full manuscript at some point and asked for revisions;
Agent GB is me.