Gparted live question

I have 2 HD's physically in my computer. When I am in gpart live GUI, in the top right hand corner of the GUI, I click on the arrow where it lists my hard drives as

/dev/sda (465GB)
/dev/sdb (74GB)
/dev/sdc (3GB)

I don't know how, but it turned 2 HD's into 3. The question is how Do I add the space from the 3GB to the 74GB so it becomes 2 HD's again.

Can someone plz help me out with doing this in you own words. Plz keep it simple.