What will happen when this takes place?

An administrator tries to connect the vSphere 5.5 Client to an ESXi 6.x host.
What will happen when this takes place?

A.
The operation will fail, since the vSphere Client is deprecated in vSphere 6.x.

B.
The operation will fail and the administrator will need to delete the client and install the 6.x version.

C.
The operation will prompt the administrator to run a script to upgrade the vSphere Client.

D.
The operation will update the vSphere Client silently in the background, then connect.