Answer
(a) Less reactants.
(b) Less reactants.
(c) Less reactants.
(d) More reactants.
Work Step by Step
Increasing the temperature favors the endothermic reactions (with positive $\Delta H^o_{rxn}$), and decreasing it favors the exothermic reactions (negative $\Delta H^o_{rxn}$).
Therefore: if the forward reaction is endothermic, decreasing the temperature favors reactants, if it is exothermic, decreasing the temperature favors products.
(a) Negative: Exothermic: Favors Products: Less reactants.
(b) Negative: Exothermic: Favors Products: Less reactants.
(c) Exothermic: Favors Products: Less reactants.
(d) Endothermic: Favors Reactants: More reactants.
