Which two approaches will meet this requirement?

The leadership team at Get Cloudy Consulting has identified a total of ten text fields on the Contact object as critical.

The team wants to capture any changes made to these fields, including the following:

– who made the change

– when they made the change

– what is the old value

– what is the new value

Get Cloudy Consulting needs to be able to report on these field data changes within Salesforce for the past 3 months.

Which two approaches will meet this requirement? (Choose two.)
A . Create a workflow to evaluate the rule when a record is created and use field update actions to store previous values for these ten fields in ten new fields.
B . Create a Contact report including these ten fields and Salesforce Id, then schedule the report to run once a day and send email to the admin.
C . Write an Apex trigger on Contact after insert event and after update events and store the old values in another custom object.
D . Turn on field Contact object history tracking for these ten fields, then create reports on contact history.