How can these requirements be met?

Universal Containers is implementing a new lead status process and wants to be able to do the following:

– Track leads through five different status values

– Run reports showing the duration a lead spends in each status

– Run full Lifetime reports of a lead from creation to conversion

– Prevent leads from skipping a lead status

How can these requirements be met?
A . Use lead history reporting to track changes in the lead status field, and use custom reporting fields to calculate status duration. Use validation rules to prevent status skipping
B . Use custom date fields and workflow rules for each status, and use custom formula fields for calculating duration of a status. Use validation rules to prevent status skipping
C . Use an Apex Trigger to populate custom date fields for each status, and use custom formula fields for calculating duration of each status
D . Use field history tracking on the lead status field to track the duration of each status. Use validation rules to prevent status skipping