You need to ensure that the Web Part can access the local file system on the SharePoint server

You create a Visual Web Part in SharePoint Server 2010. You need to ensure that the Web Part
can access the local file system on the SharePoint server. You must minimize the amount of
privileges assigned to the Web Part. What should you do?

A.
Elevate the trust level to Full.

B.
Elevate the trust level to WSS_Medium.

C.
Create a custom code access security (CAS) policy.

D.
Deploy the Web Part to the Global Assembly Cache (GAC).