  We study the relative contribution of partonic sub-processes to D meson
production and D meson-triggered inclusive di-hadrons to lowest order in
perturbative QCD. While gluon fusion dominates the creation of large angle
DD-bar pairs, charm on light parton scattering determines the yield of single
inclusive D mesons. The distinctly different non-perturbative fragmentation of
c quarks into D mesons versus the fragmentation of quarks and gluons into light
hadrons results in a strong transverse momentum dependence of anticharm content
of the away-side charm-triggered jet. In p+A reactions, we calculate and resum
the coherent nuclear-enhanced power corrections from the final state partonic
scattering in the medium. We find that single and double inclusive open charm
production can be suppressed as much as the yield of neutral pions from
dynamical high-twist shadowing. Effects of energy loss in p+A collisions are
also investigated phenomenologically and may lead to significantly weaker
transverse momentum dependence of the nuclear attenuation.
