Is there a molecule which activates p75 (the low affinity nerve growth
factor NGF) but not Tyrosine Kinase A, B, or C receptors? (Please
include references)

I am not yet an expert so this may end up helping someone make money
but I figured what the heck :)

Seems that there are molecules that activate one receptor better than
the others but I can't seem to find that exclusively activates p75

It seems that recent studies have shown that a "neurotrophin precursor
protein and its proteolytically processed products may differentially
activate pro- and antiapoptotic cellular responses, through
preferential activation of
Trk or p75 receptors."

The best review I found so far is at
http://nsm1.utdallas.edu/bio/Dmello/DEV-NEURO/NEUROTROPHIC%20FACTORS/neurotrophin-processing.pdf

Neurotrophins: To Cleave or Not to Cleave
Moses V. Chao and Mark Bothwell
Neuron, Vol. 33, 9?12, January 3, 2002, Copyright ?2002 by Cell Press

I hope this helps.  I have a call out to a researcher in one of these
labs (who I know) and will see if I can get any more info.