Consider the following equilibrium system:
C (s) + CO₂ (g) → 2CO (g) ∆H⋎°= +120 kJ

Indicate the shift in equilibrium, if any, for each of the following scenarios:
a) Adding CO₂ (g)
b) Adding C (s)
c) Lowering the temperature
d) Increasing pressure
e) Adding a catalyst