|That is assuming that you anti-virus application has such a facility, not all do.|
There is a lot of stuff that goes on drive C: that really doesn't have to. Its just a matter on knowing which. The simplest solution is not to install you anti-virus on drive C: in the first place.
Without knowing the size of your hard drive, the information is only relevant to yourself. I have 20 Gbs free on drive C:. Anti anti virus backup is going to have problems filling that.
If you continue to publish your Email address in a public forum you are going to need a good anti virus application more than most. Your Email address will be harvested and you will get more spam and mall-ware than you ever thought possible.