You have a computer named Computer1 that has the following four hard disk drives installed:
Drive 1: A 500-GB OS volume
Drive 2: A 400-GB data volume
Drive3: A 400-GB empty volume
Drive 4: A 500-GB empty volume
You need to create a two-way mirror by using Storage Spaces. The solution must minimize data loss.
Which drives should you use?

A.
Drive 1 and Drive 2

B.
Drive 1 and Drive 4

C.
Drive 2 and Drive 3

D.
Drive 3 and Drive 4

Explanation:
http://www.windowscentral.com/how-use-storage-spaces-windows-10