Which solution should a data architect recommend to encrypt existing fields?

Universal Container has implemented Sales Cloud to manage patient and related health records. During a recent security audit of the system it was discovered that same standard and custom fields need to encrypted.

Which solution should a data architect recommend to encrypt existing fields?
A . Use Apex Crypto Class encrypt customer and standard fields.
B. Implement classic encryption to encrypt custom and standard fields.
C. Implement shield platform encryption to encrypt and standard fields
D. Expert data out of Salesforce and encrypt custom and standard fields.

Answer: C