Thank you for responding, unfortunately, I am not technologically inclined, and have no idea how to post pictures on the internet. I've already had 2 plumbers tell me the same thing. At first I thought the first plumber just wanted big $$$, but when the 2nd guy said likewise I realize something's VERY wrong. Apparently most AC units don't have a drain going to the kitchen sink. It usually goes to a bathroom sink.

Tennessee. There is just a regular insulated sheet rock wall that separates the garage from the kitchen. The drain comes out of the wall and goes into the garbage disposal and also loops down and up into the p-trap and into the other pipe that goes into the other drain. I have a double bowl sink now and am getting a single bowl. I'm sorry I don't know all the correct plumbing terms. Plumbing has never been my forte. (along with technology)

The AC unit is upstairs in an attic, and the line somehow comes down into the kitchen sink.

River Valley Cabinet Works and ReSquare Architecture, thank you for your help. yes, it's pretty scary. It's common in TN to have the AC in the attics, but it makes it a little tricky to change the filters sometimes. The condensate drain is in the kitchen probably because the AC unit is directly above the kitchen , and the shortest distance between 2 points is a straight line. (just a guess) Whoever installed it probably was only thinking about getting the job done, and never considered any future renovations.
Regarding the general contractor, that is excellent advice, I just wish I knew that before this process began. I had no idea that putting in new countertops with a sink and garbage disposal could be such an ordeal! Listen up fellow Houzzers! Countertop people, PLEASE give this same advice to your customers BEFORE you make the sale. It could save a lot of stress! All of us Average Joes know NOTHING about this!

Oh, one more thing, ReSquare Architecture, I will pass on your ideas to the plumber that will do the work. I really appreciate your input. Thank you so much! Double!