A star of mass, M, and radius, R, has a density profile that increases linearly with radius in the star (r) via the expressions: p(r) = Pc (1 - R ). Here pc = central density (40pts). A. Find the mass stratification, i.e., m(r) (10pts) B. Find the Pressure stratification, i.e., P(r) (10pts) C. Derive the relation between total mass of the star M and R (10pts) D. What is the average density of the star in units of the core density (10pts)