Hi
I have a TC-14B on my ED-300mm lens. I think Nikon made an TC-14 A as well. The TC-14b is for lenses over 135 mm.
Wait ... what? A or B? Here is the list of their teleconverters. It's either the II or the III for the 1.4x TC. It doesn't have anything to do with the focal length.
https://www.nikonusa.com/en_INC/IMG...converter-Compatibility/en_US_Comp_chart.html