Explanation/Reference:
Explanation
The full list of data export options available with CRM 2015 Update 1 includes:
Static Worksheet/Open in Excel Online

Static Worksheet on Page

Dynamic Worksheet

Dynamic PivotTable

The first three options provide the ability to import the exported file back, making the process of CRM data modifications even more streamlined.
Incorrect Answers:
A: Dynamic PivotTable does not support re-import.
B: If we want to allow for updates we cannot choice a static worksheet.
C: One of the most exciting changes in the redesigned CRM Data Export and Data Import is the ability to export CRM data in Excel format and re-import it back. Now, every export file brings the GUIDs associated with CRM records, and users can bulk edit and re-import the data back if required. Previously, CRM could only import data that was marked for data reimport. CRM is now intelligent enough to recognize the GUIDs of exported records and match them automatically when data is re-imported back to CRM.
References: http://www.powerobjects.com/2015/09/18/10-data-export-and-import-redesign-features-in- dynamics-crm-online-2015-update-1/