Answer:
There is nothing attached to this question so I unfortunately cannot help you
Explanation:

This reaction is called decomposition reaction, furthermore it can be said to be decomposition of limestone.
The balanced chemical equation for the reaction is ~

The most appropriate answer is B !!
Covalent bond is formed by sharing of electrons !!
Answer:
The reducing agent is Zn.
Explanation:
Let's consider the reaction between zinc and hydrochloric acid.
Zn(s) + 2 HCl(aq) ⇄ ZnCl₂(aq) + H₂(g)
This is a redox reaction, which can be divided in 2 half-reactions: reduction and oxidation.
In the reduction, H⁺ gains electrons and it is considered the oxidizing agent.
2H⁺ + 2 e⁻ ⇒ H₂
In the oxidation, Zn loses electrons and it is considered the reducing agent.
Zn ⇒ Zn²⁺ + 2 e⁻