Can I connect a Thunderbolt Display and a MacBook Retina 12" using usb-c to thunderbolt 2 adapter
Unfortunately, you cannot use your MacBook 12" with a Thunderbolt Display.

Per Apple Support, you need a Mac with a Thunderbolt connection in order to drive this display and the MacBook just doesn't have that capability



The Thunderbolt Display is more of a Thunderbolt hub with a display attached rather than a mini Display Port display with Thunderbolt compatability.

The port on the MacBook 12" (Early 2015) is USB C 3.1 only and no adapter will convert USB to TB.