Which method should be used to automate repeat opportunities when regular customers are classified as a repeat account type?

Sales reps at Cloud Kicks (CK) need to see the Opportunity amount with the Account's discount field. CK sales reps are located in different regions and use different currencies. A consultant creates a custom formula field on the Opportunity.
Which currency will the custom formula use for its value if the opportunity and account records have different currencies?

Cloud Kiks wants to implement a methodology to determine which current Leads have the most in common with Leads that have successfully has been converted in the past.
How Cloud Kicks support this requirement?

Sales reps at Universal Containers (UC) want to know when a customer or prospect Contact opens an email, they sent so they can follow up with the Contact shortly afterward. Which tool should a consultant recommend to meet the requirement?

Northern Trail Outfitters (NTO) sells two product lines that each use a distinct selling methodology. Additionally each product line captures different information that is used to sell the products. What should a consultant recommend to support selling the two product lines?