My new pc has Windows 10. Because I need Bitlocker I upgraded to Windows 10+  When I started Bitlocker - for no good reason I applied it to the unused "D" drive partition.  I saved the Identifier and Recovery Key and also put in a Password.

Now I am trying to encrypt the "C" Drive.  Again, I have an Identifier and Recovery Key - different to the ones for the "D" drive, but I was not asked for a Password for the "C" drive. 

On accessing Bitlocker through Control Panel  I find a screen which says "(C) Bitlocker encrypting."

This is fine but what about a Password?  Does the "D" drive password work on the "C" drive as well?