Selecting verticies with "C" key not being done right

Hello all, when I make a plane and scale it big and subdivide the verticies a few times all is good untill I use the selection tool (C key) the one in a circle and when I left click to select the verticies with this tool it adds extra verticies that I havnt selected some near and some far, I dont want to shift + right click to remove them is there a way to make it so that only the selection is the ones I get? Thanks, gabrielsab.