You need to activate Office 365 ProPlus on the Surface …

You manage client computing devices for a company. Office 365 was recently deployed for all employees in the
sales department. Company policy requires the installation of Office 365 ProPlus on all new client computing
devices for sales department employees.
The company recently purchased Surface Pro 2 devices for all sales department employees. You are testing a
new Office deployment for a specific user on a Surface Pro 2. You are unable to activate Office on the Surface
Pro 2. An error message states that the install limit has been reached.
You need to activate Office 365 ProPlus on the Surface Pro 2 for the user.
What should you do?

A.
Sign in to the Office 365 portal as the user and deactivate unused Office 365 ProPlus licenses.

B.
Sign in to the Office 365 admin center as an Office 365 administrator. Remove and then re-add the user’s
Office 365 ProPlus license.

C.
Install a licensed copy of Office Professional Plus 2013 that is covered under a volume licensing agreement.

D.
Sign in to the Office 365 admin center as an Office 365 administrator and deactivate unused Office 365
ProPlus licenses.

Explanation:
Office 365 ProPlus license permits a user to install Office on a maximum of five devices. For the user to install
office on a 6th device, one of the devices that Office was previously activated on must be deactivated.
http://technet.microsoft.com/en-us/library/gg982959(v=office.15).aspx