Across a normal shock wave in a converging-diverging nozzle for adiabatic flow, which of the following relations are valid?
a. Continuity and energy equations, equation of state, isentropic relation
b. Energy and momentum equations, equation of state, isentropic relation
c. Continuity, energy and momentum equations, equation of state
d. Equation of state, isentropic relation, momentum equation, mass — conservation principle