A customer has a Dell EMC SC9000 array with six SC420 enclosures running SCOS 7.3. The enclosure configuration is as follows:

• Two enclosures have write-intensive SSDs
• Four enclosures have read-intensive SSDs

What is recommended as a general guideline for making spare drive assignments?

A. 2 spare drives per shell
B. Dedicated spares are not required
C. 2 spares per drive type per array

D. 1 spare per drive type per shell