  There are a number of candidate sources that are considered to be responsible
for the origin of the EGRET source 3EG J1746--2851 (Hartman et al. 1999). The
lack of clear identification of this source with any known sources in this
region is due to the complexity and the richness of the environment of the
Galactic center as well as the low spatial resolution of the EGRET
observations. Four hypotheses, which include the interaction of something with
something else, are described to account for the energetics and the spectrum of
the $\gamma$-ray emission from the enigmatic EGRET source which lies within
0.2$^0$ of the Galactic center. The possible interaction sites result from the
following: i) the nonthermal filaments of the radio Arc & G0.13-0.13 molecular
cloud, ii) the supernova remnant Sgr A East & the 50 km s$^{-1}$ molecular
cloud, iii) the magnetized filaments of the Arc & M0.20-0.033 molecular cloud
and iv) the relativistic particles of the Arches cluster & its own stellar
radiations field.
