First of all thank you for the valuable response and the solutions provided. All of the solutions were exactly to the point and i think this thread will be valuable to others as well.
Glenn you got the point and thank you.
Even though the solutions work, i prefer working with macros instead of formulas. So i kept the kvsrinivasamurthy solution who i honestly thank.
I added the Target.Offset(0, 2) = "" on the first part of the code so that the rest of the choice cells to be cleared also when the user makes the choice on the first one.
The only bug i find is that when i replace the name Set SecRng = Range("C3:C25") with Set SecRng = Worksheets("Sheet2").Range("C3:C25") does not work and the outcome is kind of messed up. When i try this on the same sheet it works fine. Is the Intersect function buggy when the source data are in another worksheet?