Answer the case-based question given below.
 
Redox reactions are those reactions in which oxidation and reduction occur simultaneously. A redox reaction is made up of two half reactions.
 
a. Which of the following is a redox reaction?
 
b. For the following reactions, identify the one in which \(H_2S\) acts as a reducing agent.
 
c. In the following reaction, which substance is reduced?

\(ZnO + CO ⟶ Zn + CO_2\)
 
d. In the following reaction, which substance is reduced?

\(PbS + 4H_2O_2 ⟶ PbSO_4 + 4H_2O\)